Preface

Evaluation of patients with thoracoabdominal trauma is often a diagnostic challenge for

emergency physicians and trauma surgeons. The use of ultrasound became a standard for trauma

centers throughout the world. In fact, in many trauma centers bedside ultrasound has become the

initial imaging modality used to evaluate the abdomen and chest in patients who present with

blunt and penetrating trauma to the torso.

Bedside ultrasonography in the evaluation of trauma patients has been given name the FAST

exam as a limited ultrasound examination, focusing on the detection of free fluid in abdominal,

pleural and pericardial cavities, and also pneumothorax. The FAST provides the emergency team

by valuable diagnostic information within several seconds or minutes allowing for rapid triage of

patients with unstable hemodynamic.

Its success and growing popularity are in large part due to the fact that the examination is

noninvasive and accurate and can be easily performed by emergency physicians and trauma

surgeons with limited training. The FAST examination performed rapidly by the treating

emergency physicians and trauma surgeons, who first face the trauma patients, allows to timely

diagnosis and improves patient management, enhances patient safety, and saves lives.

This book just summarizes information about FAST exam from the best articles published in

well-known electronic journals, sites and books containing the information about FAST protocol

from 2000 – 2010, such as:

American Journal of Roentgenology, Radiology, British Journal of Radiology, Radiographics,

Journal of Ultrasound in Medicine, The Journal of Trauma, Emergency Med. Journal, Chest,

eMedicine, hqmeded.com, Trauma.org, sonoguide.com, Ultrasoundcases.info.

Emergency ultrasound O. John Ma, James R. Mateer, Michael Blaivas

Emergency radiology – Imaging and Intervention Borut Marincek, Robert F. Dondelinger

General ultrasound in the critically ill Daniel Lichtenstein

Manual of Emergency and Critical Care Ultrasound Vicki E. Noble, Bret Nelson, A. Nicholas

Sutingco

Ultrasound for surgeons Heidi L. Frankel

Ultrasound in Emergency Care Adam Brooks, Jim Connolly, Otto Chan

Practical Guide to Emergency Ultrasound Cosby, Karen S.; Kendall, John L.

Chest Sonography Gebhard Mathis

This book provides a simplicity and compactness for the reader who uses emergency

ultrasonography for trauma in practice and published on principles Open Medicine.

Dr.Yuliya, Ukraine, Sonologist, Mizdah General Hospital, Libya 2010

http://sonomir.wordpress.com/

Content

About FAST………………………………………..4

Anatomical considerations…………………………12

What look for first………………………………….15

Look for hemoperitoneum and hemothorax………..21

Look for pneumothorax…………………………….48

Look for hemopericardium…………………………61

Clinical value of FAST results……………………..83

Additional examinations at FAST………………….85

Emergency sonography for trauma

FAST protocol

Time-sensitive information is a cornerstone of emergency medicine. The ability to obtain and

apply crucial decision-making data rapidly is paramount. Emergency ultrasound has the basic

goal of improving patient care. The use of sonography in evaluating the patients with trauma has

rapidly expanded in the past decade. “Trauma ultrasound” is synonymous with “emergency

ultrasound.” Emergency sonography at a trauma is performed as FAST protocol

and is useful modality for the initial evaluation of patients with blunt or penetrating trauma.

FAST - Focussed Assessment with Sonography for Trauma

FAST ( Focused Assessment with

Sonography for Trauma )

This limited ultrasound examination

focused exclusively on the detection of free

fluid in abdominal cavity, pleural and

pericardial cavities, and also detection of

pneumothorax.

Speed is important.

Examination should be performed quickly

(during 3 - 3.5 minutes).

Abdominal part of the FAST examination provides a quick overview of the intraperitoneal cavity

to detect free fluid, which is an indirect sign of visceral organ injury.

At FAST protocol 8 standard points are investigated:

In RUQ look for fluid in the perihepatic space and

right pleural cavity.

In LUQ look for fluid in the perisplenic space and

left pleural cavity.

In suprapubic area look for fluid in a pelvis.

In subcostal area look for fluid in a pericardium.

In the upper anterior chest look for pneumothorax.

Performance of the FAST protocol.

Investigation of the RUQ (Right Upper

Quadrant).

Look for fluid in the hepatorenal space

(Morison's pouch) and right

subdiaphragmal space, and also look for

fluid in the right pleural cavity.

Performance of the FAST protocol.

Investigation of the LUQ (Left Upper

Quadrant).

Look for fluid in the splenorenal space

and left subdiaphragmal space, and also

look for fluid in the left pleural cavity.

Performance of the FAST protocol....……...

Subcostal (subxifoid) view.

Look for fluid in a pericardial cavity.

Performance of the FAST protocol. ..............

Pelvic view.

Look for free fluid in a pelvis.

Performance of the FAST protocol.………………………..

Upper chest view.

Look for pneumothorax.

Why FAST

Ultrasonography is highly sensitive for detection of hemoperitoneum (as indirect sign of

intraabdominal injury) but not sensitive for the identification of organ injury as source of

hemoperineum. The numerous studies demonstrates that ultrasonography as method has low

sensitivity (41 %) for detecting organ injuries. Even at large lacerations the parenchymal organs

can appears normal at ultrasound examination. And abdominal injuries which are not associated

with hemoperitoneum can be easily missed. Ultrasonography is limited and unable to show some

types of injuries, including bowel and mesentery injuries, pancreatic injuries, vascular injuries,

diaphragmatic ruptures, renal and adrenal injuries.

Unlike Ultrasonography, CT has ability to precisely locate intra-abdominal injuries

preoperatively, to evaluate the retroperitoneum, to identify injuries that may be managed

nonoperatively. CT comprises the majority of diagnostic imaging in blunt abdominal trauma and

remains the criterion standard for the detection of solid organ injuries, however CT has

disadvantages including: ionizing radiation, IV injection of radioiodinated contrast material, it is

expensive, time-consuming, and requires that the patient be stable in order to be transported out

of the ED, because the patient is less monitored during transportation and CT scanning (thus the

trauma adage “death begins in radiology”).

Ultrasonography has advantages compared with DPL and CT: it is sensitive for hemoperitoneum

and can be performed quickly and simultaneously with other resuscitative measures, providing

immediate information at the patient's bedside, simple, noninvasive, repeatable, portable, and

involves no nephrotoxic contrast material or radiation exposure to the patient, and readily

available screening examination, and can be performed by non-radiologists (emergency

physicians and trauma surgeons). In most medical centers, the FAST examination has virtually

replaced DPL (diagnostic peritoneal lavage) as the procedure of choice in the evaluation of

hemodynamically unstable trauma patients.

The FAST examination is based on the assumption that all clinically significant abdominal

injuries are associated with hemoperitoneum. Sensitivity FAST in detecting of a free fluid in

abdominal cavity is 63 - 100 % (depends on quantity of a detectable fluid and operator

experience), specificity 90 - 100 %. Rozycki et al reported that ultrasound is the most sensitive

and specific modality for the evaluation of hypotensive patients with blunt abdominal trauma

(sensitivity and specificity, 100%).

So, FAST is effective initial triage tool to evaluate trauma victims with suspected blunt

abdominal injuries, which performed rapidly in the admission area. For the unstable patient,

rapid and accurate triage is crucial because delayed treatment is associated with increased

morbidity and mortality. To mitigate morbidity and mortality, rapid determination of which

patients with intraabdominal injuries require surgical exploration is critically important.

Hemodynamically stable patients with positive FAST results may require a CT scan to better define the nature and extent of their injuries. Taking every patient with a positive FAST result to

the operating room may result in an unacceptably high laparotomy rate.

Hemodynamically stable patients with negative FAST results require close observation, serial

abdominal examinations, and a follow-up FAST examination. However, strongly consider

performing a CT scan, especially if the patient has other associated injuries.

Blunt abdominal trauma algorithm

Hemodynamically unstable patients with negative FAST results are a diagnostic challenge.

Options include DPL, exploratory laparotomy, and, possibly, a CT scan after aggressive

resuscitation.

In unstable patients with a negative FAST exam, extraabdominal sources of hypotension must be

carefully ruled out (intrathoracic trauma, blood loss from extremity trauma, spinal shock, head

injuries). DPL can also be performed if FAST images are not clear or difficult to obtain for

technical reasons (subcutaneous air, bowel gas).

Therefore the FAST is initial screening tool for rapid triage of victims for immediate laparotomy

at detecting of the hemoperitonium in patients with unstable hemodynamic and for the

subsequent diagnostic tests at positive or negative FAST results in patients with stable

hemodynamic.

Also ultrasonography is highly sensitive for detecting hemothorax, pneumothorax and

hemopericardium, providing rapid information, and allows to emergency action at tamponade or

pneumothorax.

The FAST examination is included in ATLS protocol, performing in a resuscitation area.

Performance of the FAST protocol

during resuscitation.

FAST is performed simultaneously with

physical assessment, resuscitation, and

stabilization of the trauma patient.

Primary function of the radiologist or sonologist is to perform FAST, in order to evaluate for free

peritoneal fluid and to exclude hemodynamically significant abdominal injuries. Speed is

important because if intraabdominal bleeding is present, the probability of death increases by

about 1% for every 3 minutes that elapses before intervention.

This quick study takes 3 – 3.5 minutes (2 – 2.5 minutes on searching for fluid in abdominal

cavity, pericardial and pleural cavities, plus 1 minute on searching for pneumothorax). The

average time to perform a complete FAST examination of the thoracic and abdominal cavities is

2 minutes to 4 minutes. At massive hemoperitonium examination only one point (pouch of

Morison) allows to diagnose within several seconds.

Also important rapidity with subsequent triage of patients, especially at a large numbers of

traumatically injured victims (natural disasters, terrorist attacks and military mass casualty

events). To provide rapid reports that could be used instantly, can be applied colored stickers that

are attached the patient's chart: red when positive for free peritoneal fluid, green when negative,

and yellow when indeterminate. These are attached to the patient's chart in a clearly visible way

to alert the staff as to whether the patient needs prompt further evaluation.

Rapid interpretation of the FAST result.

Red label - positive FAST

Green label - negative FAST

Yellow label - indeterminate FAST

This system is visually effective for expeditious reporting of results to all personnel involved in treating the patient in a clear and unequivocal manner. And helps for rapid triage of victims: who

need for promt laporotomy and who need for immediate further evaluation (CT, MRI, DPL,

angiography).

With the development of sophisticated handheld or

highly portable ultrasound equipments the value of this

rapid and accurate technique is becoming apparent in the

pre-hospital environment (in ambulance, helicopters and

planes).

Get valuable visual information at the first point of

contact - reducing delays, when time is a matter of life

and death.

A prehospital FAST (PFAST) may indicate abdominal injury before the patient reaches the

hospital, which can increase the effectiveness of trauma management. PFAST can be performed

an average of 35 minutes earlier than a FAST or CT in the emergency department. When a

patient has a positive PFAST at the scene, prehospital care is minimized, allowing for quicker

transport to an appropriate hospital or trauma center. In addition, the health care team at the

awaiting hospital can be contacted prior to the patient‟s arrival, providing additional time to

prepare and improving overall patient management. PFAST in remote settings using wireless and

satellite transmission, can be helpful in isolated military locations and mass casualty situations.

A satellite transmitter sends the ultrasound images immediately to a hospital for interpretation by

a radiologist or emergency physician.

FAST history

The use of ultrasound in the evaluation of the traumatically injured patient originated in the

1970s when trauma surgeons in Europe (Germany) and Japan first described sonography for

rapid detection of life-threatening hemorrhage. The German surgery board has required

certification in ultrasound skills since 1988.

The experience of physicians in the United States with ultrasound in the setting of trauma came

to publication in the early 1990s.

The acronym FAST, standing for “Focused Abdominal Sonography for Trauma”, or the FAST

exam (as a limited ultrasound examination, focusing primarily on the detection of free fluid in

abdominal cavity) appeared in a 1996 article in the Journal of Trauma, written by Rozycki.

FAST rapidly developed to regions beyond the abdomen (including evaluation of the

heart and the pleural spaces) and in recognition of this the term „Focused Assessment with

Sonography for Trauma‟ was accepted at the International Consensus Conference in 1997.

Ultrasound proved to be such a practical and valuable bedside resource for trauma that it

received approval by the American College of Surgeons and was incorporated into standard

teaching of the Advanced Trauma Life Support curriculum. The FAST exam has

been included as part of the ATLS course since 1997.

Who can perform FAST

Critical condition in trauma patient requires immediate treatment for rescue of life of the patient

and directly depends on rapidity of an establishment of the diagnosis. Ultrasonography is the

fastest and accessible method in this situation.

FAST protocol should be performed as soon as possible. But it may be impossible in a number

of institutions for the radiologist or sonologist to provide 24-hour coverage for trauma US.

Therefore researches were looked for possibility of performing FAST protocol by doctors non-

radiologists, who first face the trauma patients (emergency physicians and trauma surgeons).

Performance of the FAST protocol by surgeons has begun in Germany and Japan. The researches

showed, that FAST protocol (which is relatively simple in performing and interpretation of

results) was successfully performed by well trained non-radiologists doctors and also results

were slightly different from the results obtained by skilled radiologists or sonologists.

And now, the FAST protocol can be performed by any specialists (not necessarily by a

sonographers, sonologists or radiologists), which adequately trained in this method, aiding in the

immediate availability of this technique in the emergency situation.

Ability ultrasonography quickly provides

clinically significant information at

performance FAST protocol explains the

raised popularity of this method among

emergency physicians and trauma surgeons.

The American College of Surgeons has included ultrasound as one of several “new technologies”

that surgical residents must be exposed to in their curriculum. Both the American College of

Emergency Physicians and the Society for Academic Emergency Medicine support the use of

ultrasound to evaluate blunt abdominal trauma as well. Since 2001, training in emergency

ultrasound has been required for all emergency medicine residents. All physicians who will be

evaluating trauma patients must become proficient in the use of trauma ultrasound.

A FAST trained military surgeon utilizing handheld ultrasound to

assess a casualty with blunt abdominal trauma in a field hospital

environment.

A course in FAST ultrasound has been developed for UK military

surgeons who are now using the technique to assess casualties

when no support from a sonographer or radiologist is available.

One study showed that 10 examinations is sufficient for successful performance of the FAST,

but was overturned by subsequent studies, which demonstrated that 10 examinations are not

sufficient for comprehensible results of FASТ due to errors.

Therefore experience has great importance for adequate results and last researches shows that the

200 or more supervised examinations are necessary for credentialing in FAST.

Anatomical considerations

The spleen is the most commonly injured abdominal organ, occurring in one-third of all patients

with blunt abdominal trauma.

After the spleen, the liver is the second most commonly injured organ in blunt abdominal

trauma, occurring in approximately 20 % of all patients with blunt trauma. Injury to the right

lobe is far more common than the left lobe. Injury of the posterior segment of the right lobe is

more common than anterior segment. But at the combined trauma (blunt and penetrated) most

often injured organ is the liver. The caudate lobe of the liver is damaged rare.

Injuries of the bowel and mesentery occurs in 5 % of patients. Usually the bowel and mesentery

are injured together, but also can be isolated injured. Urinary bladder injury is not common in

abdominal trauma (1.6 %). Pancreatic injuries are rare, occurring in 0.4 % of patients.

The site of accumulation of intraperitoneal fluid is dependent on the position of the patient and

the source of bleeding. Hemoperitoneum starts in site of laceration, then blood flows and

accumulates in dependent intraperitoneal compartments formed by peritoneal reflections and

mesenteric attachments.

In the supine patient, free intraperitoneal fluid accumulates in 3 potential places: in hepatorenal

space (Morison's pouch is the potential space between the liver and the right kidney), in

splenorenal space and in a pelvis (in pouch of Douglas in women and in retrovesical pouch in

men).

Transverse illustration of the upper

abdomen that demonstrates the

dependent compartments where free

intraperitoneal fluid may collect.

The free fluid in hepatorenal pouch

(Morison's pouch) and in splenorenal

pouch (red spaces).

Free fluid from the lesser peritoneal

sac will travel across the epiploic

foramen to Morison's pouch.

Longitudinal illustration of the right

paramedian abdomen which

demonstrate the dependent

compartments where free

intraperitoneal fluid may collect.

Blood collects in Morison's pouch

and then flows to pelvis through the

right paracolic gutter.

Free intraperitoneal fluid in the right upper quadrant will tend to accumulate in Morison's pouch first before overflowing down the right paracolic gutter to the pelvis. In contrast, free

intraperitoneal fluid in the left upper quadrant will tend to accumulate in the left subphrenic

space first, and not the splenorenal recess, which is the potential space between the spleen and

the left kidney. Free fluid overflowing from the left subphrenic space will travel into the

splenorenal recess and then down the left paracolic gutter into the pelvis. Free fluid from the

lesser peritoneal sac will travel across the epiploic foramen to Morison's pouch. Free

intraperitoneal fluid in the pelvis will tend to accumulate in the rectovesical pouch in the supine

male and the pouch of Douglas in the supine female.

Blood flow pattern within the

abdominal cavity (black spaces,

arrows).

The right paracolic gutter connects

Morison's pouch with the pelvis.

Free fluid overflowing from the left

subphrenic space will travel into the

splenorenal recess and then down the

left paracolic gutter into the pelvis.

The left paracolic gutter is more shallow than the right and its course to the splenorenal recess is

blocked by the phrenicocolic ligament. Thus, free fluid will tend to flow via the right paracolic

gutter since there is less resistance. In the supine patient, the most dependent area is Morison's

pouch, independently from site of laceration.

Overall, however, the rectovesical pouch is the most dependent area of the supine male and the

pouch of Douglas is the most dependent area of the supine female.

Large volume of blood may accumulate in a pelvis without collection of the blood surrounding a

source of a bleeding.

An isolated pelvic view may provide a slightly greater yield (68% sensitivity) than does an isolated view of Morison's pouch (59% sensitivity) in the identification of free intraperitoneal

fluid.

Fluid location may be helpful. Triangular or polygonal fluid collections which located centrally

between bowel loops are uncommonly associated with solid organ injury and more likely to be

related to bowel or mesenteric injury. Unlike liver and spleen injuries, where the fluid usually

flows to pelvis on periphery (in paracolic gutters) and not accumulates centrally between bowel

loops. So, detection of free intraperitoneal fluid between bowel loops raises the suspicion for

bowel or mesenteric injury even in the presence of solid organ laceration.

Also it is necessary to remember, what even significant abdominal injuries can be without

hemoperitonium as intraparenchymal lacerations can be without rupture of capsule.

Preparation for examination

FAST is performed using abdominal probe with

frequency 3.5 - 5.0 MHz. For some parts of the extended FAST can be used high

frequency probe.

But FAST is virtually can be performed by one probe for

all areas of the examination.

For protection of the probe against pollution by blood at examination of trauma patients, and also

protection of the patient against infections at a large numbers of traumatically injured victims,

the cover or a medical glove which dresses on the probe is used, changing for each victim. A

small amount of gel is put on the probe (for contact) and then covered by medical glove.

Rapid application of gel on all standard points before

examination allows not to distract during scanning

and shortens time of the examination.

At performing of the FAST full urinary bladder is necessary. Pelvic view is easier to obtain when

the bladder is full and prior to the placement of a Foley catheter. Without a full urinary bladder

as an ultrasonic window, free fluid in the pelvis is easily missed. But it is not uncommon that a

Foley catheter is inserted in trauma patients to look for hematuria and monitor urinary output. If

it is performed before the FAST scan, need to re-fill the urinary bladder with 200 ml saline

through the Foley catheter. Beware the excessively full bladder, because a grossly distended

bladder may obliterate the rectovesical pouch (or pouch of Douglas) and empty it, giving a false-

negative result, thus, a partially voided study may increase sensitivity.

What look for first

The sequence of the standard points of the FAST examination is a greatly depends on the clinical

scenarios. The sequence of areas of the examination in hemodynamically stable patients has little

importance, because of the FAST protocol is performed quickly (within 3-3.5 minutes).

But it has huge value in hemodynamically unstable patients (with systolic pressure 90 mm Hg or

less) and especially in critically ill patient without palpable pulse in the presence of cardiac

electrical activity on monitor - PEA (Pulseless Еlectrical Аctivity). In such situations patients

should be promptly assessed with focused echocardiography since a sonographic picture of the

heart may provide an immediate understanding of the causes.

Focused echocardiography in trauma patient.

Look for pericardial effusion, filling pattern, heart rate.

Usually is used subcostal window (1) but if it is impossible to

obtain quickly adequate scan, immediately should be performed

parasternal scanning (parasternal long axis view) (2).

A focused assessment of the inferior venous cava (IVC) diameter is important addition to

sonographic assessment of trauma patients with minimal additional time. Because size of IVC

provides valuable information about hemodynamic.

The IVC is visualized through a subxiphoid or a right lateral window at the midaxillary line

(depending on patient body habitus and interference of bowel gas).

IVC assessment. Subxiphoid long-axis view of the inferior vena

cava.

The probe is placed longitudinally in epigastric midline with beam

direction slightly to the right side, to IVC appearance.

(or probe can displaced slightly to the right from midline).

Results of focused echocardiography and IVC diameter can provide quickly important

information about a condition of the patient and understanding of the causes of an unstable state.

Ultrasound can identify correctable causes of PEA.

3 main causes of Pulseless Еlectrical Аctivity in trauma patients:

Tamponade of the heart

Hypovolemic shock (at acute massive hemorrhage)

Tension pneumothorax

Immediate Focused Echo/IVC Triage algorithm in trauma patients

The inferior vena cava (IVC) is important to evaluate because it can provide an assessment of the

patient‟s fluid status and right atrial pressures, representing central venous pressure.

The size of the IVC provides the rapid and valuable information about pressure in the right

atrium. Measuring the maximal and minimal diameter of the vein cava, reflecting changes of its

diameter on inspiration and expiration (M - mode measurement is more accurate).

The IVC should collapse with inspiration (>50%) in the normal patient and suggests right atrial

pressures <10 mm Hg.

Dilation of the IVC (the maximum diameter > 2 cm) with reduction of collapse at inspiration is

considered evidence of elevated CVP.

Dilated IVC with collapse <50% suggests right atrial pressure >10-15 mm Hg, if dilated IVC is

not collapsed right atrial pressure >15 mm Hg.

Elevation of right atrial pressure in a trauma context is characteristic for cardiac tamponade and

tension pneumothorax (due to "obstruction" circulation caused by an external compression of the

heart chambers).

Subxiphoid IVC view. Longitudinal scanning of IVC in supine

patient.

Probe is placed longitudinally just below the xyphoid process in

epigastric midline with beam direction slightly to the right side

until IVC will be appear, just under caudate lobe of the liver.

Follow the IVC up until it is seen entering the right atrium.

Anatomic markers for IVC detection are a caudate lobe

of the liver (arrow), as IVC is located just under

caudate lobe, and the right atrium (RA), as IVC is

entranced into the right atrium (this place is easily

defined because of heart motions).

The maximal antero-posterior diameter of the IVC is

measured at both end inspiration and end expiration

(minimal and maximal IVC diameters). These

measurements are taken within 2 cm of its entrance into

the right atrium.

The pitfall of this view includes the misidentification of the aorta for the IVC. This can be

avoided by careful attention to angulation. The aorta is to the left of the midline, while the IVC is

to the right of the midline. Also the IVC is seen entering into the right atrium.

Subxyphoid window. Longitudinal

scanning of the IVC.

Normally, the inferior vena cava

narrows during inspiration and distends

during expiration.

On the image a IVC with the maximal

size 1.9 cm (at expiration) and the

minimal size 0.5cm (at inspiration) –

normal respiratory IVC collapse.

At IVC examination the probe marker can be directed caudally (to feet) or cranially (to head).

Subxyphoid longitudinal view.

Tamponade of the heart.

Pericardial effusion (PE) with right atrial collapse

(RA, arrow).

Longitudinal scan of dilated IVC (2,6cm).

The diameter of dilated IVC was no changed at

respiration.

Also sonographic measurement of inferior vena cava diameter is a valuable tool in estimating

fluid status. The IVC diameter is used for evaluation of central venous pressure (CVP), as an

alternative, quick and noninvasive methods to assess volume status.

Collapsed IVC is accurately correlated with hypovolemia (hypovolemic shock) in trauma

patients and is the reliable indicator of blood loss, even in small amounts of 450 cc.

Blaivas et al. revealed a statistically significant 5 mm decrease in IVC diameter was seen after

donation of 450 cc blood in healthy donors.

So, IVC collapse is a marker of blood loss and this information helps to diagnose bleeding at

blunt abdominal trauma even before detection of its source.

Hypovolemia is increasingly likely with IVC diameters less than 1 cm. This information allows

quickly estimate the volume status (the patient is hypovolemic or not hypovolemic). Because not

all hypotensive trauma patients are hypovolemic (frequently trauma patients with other non-

volume related causes of shock are seen).

Subxyphoid window.

Longitudinal scanning of IVC.

Collapsed IVC in trauma patient with massive

intraperitoneal bleeding.

Maximal diameter of IVC measuring about 0.3–0.4

cm.

Diameter is measured about 2 cm from the

caval–atrial junction.

The right atrium and hepatic vein are also seen.

Flat IVC in a patient who had been involved in a traffic accident.

Contrast-enhanced CT scan reveals a flattened IVC (black

arrow). Gross hemoperitoneum (white arrow).

Presence of a flattened inferior vena cava ("flat cava" sign) is a

strong indicator of hypovolemia (blood loss in trauma patient).

Detecting blood loss in trauma patients can often be challenging when an obvious source of

hemorrhage is not readily seen.

CVP also can be estimated by sonographically evaluating the internal jugular vein, especially if

the IVC view impossible to obtain. Ultrasound of the internal jugular vein is a simple

examination that can be performed by a sonographer of any skill level and offers a noninvasive

way to estimate CVP.

Internal jugular vein is easily seen on ultrasound.

In a patient with an elevated CVP the internal jugular vein will appear

distended.

In a patient with a low CVP the internal jugular vein will appear

collapsed.

FAST technique

Examination of the Right Upper Quadrant

In Right Upper Quadrant look for fluid in the perihepatic space (hepatorenal pouch and right

subdiaphragmal space) and in the right pleural cavity.

Look for fluid in Morison's pouch

Looking for free fluid in abdominal cavity is recommend to start with a Morison's pouch,

because hepatorenal pouch is the earliest and most frequent place of a blood collection at blunt

abdominal trauma. One large study (10300 patients with blunt and penetrated trauma) demonstrated, that

hepatorenal pouch was positive more often, than splenorenal pouch at the isolated injury of a

spleen.

Also scanning of a Morison's pouch is relatively easy and rapid.

The patient in supine position. The probe is

placed in the mid-axillary line between 11th

and 12th ribs, applying coronary scan with

sliding by the probe (cranially or caudally

and medially or laterally) for obtaining the

optimal image of Morison's pouch and

looking for blood in it.

Also successfully can apply longitudinal scan of the right upper quadrant in anterior-axillary

line, searching for blood in Morison's pouch.

Rib shadows can cause poor acoustic

window. In such situation probe should be

placed between ribs (along the intercostal

space).

The hepatorenal pouch (Morison's pouch) is a

space between the right lobe of the liver and

the right kidney, which closely adjacent to

each other.

At the presence of free fluid in abdominal

cavity the Morison's pouch is a potential place

of fluid collection. Liver and right kidney will

separated by fluid in Morison's pouch. Than

more fluid than more separation of these

organs.

At Morison's pouch scanning must be obtained image of the right lobe of the liver and the right

kidney. The attention should be focused on searching for fluid (anechoic space) between these

two organs.

Correct imaging.

Only when liver, right kidney and a diaphragm

will be together displayed on the image and well

visualized, only then scan will be considered as

correct.

Normally, on US image the right kidney is

closely adjacent to the liver, without separation

these organs by anechoic (black) space.

At the presence of free fluid in the Morison's pouch liver and right kidney will separated by

anechoic space (from thin stripe, if small amount of fluid is present, to significant separation of

these organs, if large amount of fluid is present in Morison's pouch). In cases of acute

hemoperitoneum, blood appears as an anechoic space in the recess, as depicted in the images

below.

Small amount of fluid in the Morison's pouch......

Blood in the Morison's pouch as anechoic stripe

between the liver and kidney.

Blood in the Morison's pouch (the liver and the

right kidney are more separated by anechoic

fluid).

Large amount of blood in the Morison's pouch

(the liver and the right kidney are markedly

separated by anechoic fluid).

In critical situations, in patients with marked hemodynamic instability, the detection of fluid in pouch of Morison (as marker of hemoperitoneum) is indication for performing immediate

laparotomy.

Massive hemoperitoneum.

A significant amount of the fluid surrounding a

liver due to splenic laceration.

Anechoic free fluid accurately outlines pouchs of intraperitoneal cavity and contours of organs.

A large amount of fluid in a pouch of Morison is easily and quickly detected, without causing

difficulties in diagnose of hemoperitoneum. But difficulties can arise at small amount of fluid.

Liver laceration in a 33-year-old man

involved in a motor vehicle accident.

Longitudinal scan of the right upper

quadrant. The small amount of blood in the

Morison's pouch (arrow).

CT was performed at the same time as the

US scan and large liver laceration was

detected.

For avoiding errors, a Morrison's pouch also should be scanned with transverse plane, rotating the probe on 90 degrees. This method raises diagnostic accuracy at detection of the presence of

fluid in hepatorenal pouch (especially if minimal amount of fluid is present).

Investigation of the hepatorenal pouch with

transverse scanning.

The minimal amount of blood in a Morrison's

pouch.

The patient with spleen rupture.

Transverse scanning of the RUQ.

The hepatorenal pouch with minimal amount of

free fluid (arrow).

Hemoperitoneum.

Transverse scanning.

Free fluid in subhepatic space and a Morison's

pouch.

The bowel wall adjacent to the liver as thin anechoic strip (also inferior vena cava or gall

bladder) should not be mistaken for free fluid.

For excluding errors, need to apply different scans, allowing to identify these structures. In such

situations perpendicular scans of these structures are usually useful.

Small bowel laceration and mesenteric tear in a

72-year-old woman involved in a motor vehicle

accident.

Longitudinal scanning of the hepatorenal pouch.

FF (free fluid) - a trace amount of free fluid in

the Morison's pouch. Anechoic stripe

representing free fluid (non vascular origin

confirmed by color Doppler).

In any doubts transverse scanning of this area

should be performed.

The minimal amount of blood in Morison's

pouch was confirmed at transverse scanning.

Liver rupture.

Longitudinal scan of the Morison's pouch.

Echogenic and a heterogeneous hematoma in the

liver.

The minimal amount of blood in Morison's

pouch.

At searching for free fluid in RUQ also it is necessary to investigate all space surrounding the

liver. Especially when in Morison's pouch free fluid is not detected.

For investigation of the space surrounding lower edge of the liver (look for free fluid in the

subhepatic space) need to displace the probe mildly downwards from position of the Morison's

pouch. The image of lower edge of the liver will be obtained. Then probe need to displace

medially by sliding movement (with direction to the left lobe of the liver). At this time attention

should be concentrated on searching for fluid surrounding the liver edges.

Hemoperitoneum. Blood at the lover edge of the

liver.

At investigation of a pouch of Morison the free

fluid was not detected, but at displacement of the

probe more caudally and medially was detected

the free fluid surrounding lover edge of the liver.

Free fluid at the lover edge of the liver (arrows)...

In the same way also should be examined upper edge of the liver (look for fluid in the right subdiaphragmal space – between liver and diaphragm). The probe need to displace a little

upwards from position of the Morison's pouch, and then probe need to displace medially by

sliding movement (with direction to the left lobe of the liver).

Hemoperitoneum. A blood in right subdiaphragmatic

space.

Anechoic space (arrow) between the upper edge of the

liver and hyperechoic diaphragm.

Massive Hemoperitoneum.

A large amount of the free fluid surrounding the liver and

the gall bladder.

In the trauma setting, free fluid usually represents hemoperitoneum, although it may also

represent bowel contents, urine, bile (due to injuries of hollow organs) or ascites.

At medical ascites (cirrhosis, heart failure) in patients with trauma FAST protocol cannot be

excluded hemoperitoneum and in hemodynamically unstable patients is considered positive,

stable patients with medical ascites should be evaluated with other diagnostic tests.

Look for fluid in right pleural cavity

After examination of the Morison's pouch the probe must be moved mildly upwards, looking for

fluid in right pleural cavity which is located above the diaphragm.

Look for fluid in right pleural cavity.

Probe is moved mildly upwards from

position of the Morison's pouch.

On US image diaphragm looks as

hyperechoic arch and is anatomic landmark

dividing abdominal cavity from a pleural

cavity.

Below the diaphragm (caudally – toward

the feet) is located abdominal cavity.

Above the diaphragm (cranially – toward

the head) is located pleural cavity.

The diaphragm acts as a strong reflector of ultrasound beams and normally, mirror image of the

liver projected above the diaphragm (because of a mirror artifact). At the presence of fluid in

pleural cavity this mirror image disappears and anechoic space above the diaphragm is

visualized.

Examination of the right pleural cavity.

No hemothorax (absence of the anechoic

space above the diaphragm).

MI – mirror image of the liver projected

above the diaphragm.

Right-sided hemothorax. Anechoic fluid (arrow) above

the diaphragm (loss of mirror image).

Right-sided hemothorax – anechoic space

above the diaphragm (yellow arrow).

In anechoic fluid visualized partially

collapsed lung with vertical comet-tail

artifacts (blue arrow).

Presence of a pleural fluid can be confirmed at

transverse scanning.

Transverse scan through the liver (L).

Pleural fluid (grey arrow)

Hyperechoic diaphragm (black arrow)

Chest wall (yellow arrow).

Also is present a free fluid in abdominal cavity

(blue arrow)

At simultaneous presence of hemoperitoneum with

right subdiaphragmal fluid and right-sided

hemothorax, the fluid surrounding the liver will be

visualized as anechoic space below the diaphragm,

and hemothorax as anechoic space above the

diaphragm.

The diaphragm will looks as hyperechoic arch

dividing these spaces.

The same image will have left sided hemothorax

with hemoperitoneum in left subdiaphragmal

space.

A large pleural collection (*) above the diaphragm

(arrows) around the collapsed right lower lobe

(arrowheads).

Also the free intra-abdominal fluid (star) below

the diaphragm.

The minimum amount of a pleural fluid which can be detected at radiography in patient with

upright position is 150 ml. Ultrasonography considerably surpasses radiography in revealing of

a pleural fluid, with sensitivity of 100 % and specificity of 99.7 %, and can reveal minimal

amount of a pleural fluid, even 5 ml.

Radiography has sensitivity of 71 % and specificity of 98.5 %, but in a prone position of patient

sensitivity more decreases (43 %) and even considerable quantities of fluid can be not detected.

Also ultrasonography is capable to estimate volume of hemothorax.

An easy to perform method of calculation of volume of a pleural liquid is:

The total of the basal lung-diaphragm distance and the lateral height of the effusion multiplied

by 70

A simple estimation of effusion volume by

measuring the height of the subpulmonary

effusion and the maximum height.

Estimated volume 700 ml, actual volume 800

ml.

At performance of the FAST protocol the quantity of a hemothorax is often estimated visually

(mild, moderate or massive hemothorax).

Massive right-sided hemothorax - a large

amount of anechoic fluid above the

diaphragm.

Collapsed lung (arrow).

Examination of the Left Upper Quadrant

In LUQ look for fluid in the perisplenic space and in the left pleural cavity.

Look for fluid in the perisplenic space

The left upper quadrant free fluid is significantly associated with splenic injury.

Examination of the perisplenic space is the most difficult part of the FAST protocol. The

perisplenic window can be quite difficult to obtain as the spleen lies more superior and posterior

than may be expected.

Unlike investigation of the right upper quadrant, left upper quadrant should be investigated along

the posterior axillary line with the transducer placement one or two intercostal spaces cephalad

compared to the right side.

Perisplenic probe position.

The probe is placed along the left posterior

axillary line between 8 and 11 ribs.

The left kidney can be used as a landmark as it will frequently be the first recognizable

structure. From the left kidney view the probe should then be moved or angled cephalad (to

head) to visualize the spleen and the interface between the two organs (splenorenal pouch).

Rib shadows can cause poor acoustic

window. In such situation probe should be

placed between ribs (along the intercostal

space).

The stomach and splenic flexure of the colon are anterior to the splenorenal space and may

prevent good images being obtained if they contain air. A posterior position of the probe

should avoid this.

A cooperative patient may be able to improve the view by taking a deep breath. Alternatively

turning the patient slightly on to their right side, if injuries allow, may be useful.

The attention should be concentrated on searching for fluid in the splenorenal pouch (between a

spleen and the left kidney), but also should be estimated all perisplenic space.

The splenorenal pouch is a space between the

spleen and the left kidney.

Searching for fluid must be performed in

splenorenal pouch and also in all space

surrounding the spleen.

Normally the surrounding tissues of these organs are in direct contact with one another.

Hemoperitoneum will seen as anechoic space between the spleen and left kidney or between the

spleen and the diaphragm.

Splenorenal View.

Splenic rupture.

Hyperechoic hematoma (yellow arrow) and

small amount of blood in the splenorenal pouch

(as anechoic strip between the spleen and the

kidney (white arrow).

The posterior subphrenic space is more dependent than the splenorenal pouch, therefore free

fluid is a frequently collects between the spleen and diaphragm. The probe from splenorenal

view should be angled more cephalad for well visualization of the spleen and diaphragm. Left

sided pleural fluid above the diaphragm can also be appreciated in this view.

But for assessment all perisplenic space the probe should be angled or moved with different

positions (superiorly or inferiorly, anteriorly or posteriorly – depends from spleen location) for

obtaining the desired images.

Hemoperitoneum. Splenic rupture. Anechoic fluid

in left subdiaphragmatic space.

Hemoperitoneum. Splenic rupture.

Free fluid at the lower pole of the spleen. The

fluid outlines the spleen edge.

Hemoperitoneum. Splenic rupture.

Irregular lower pole of the spleen surrounded by

fluid (arrow).

Hemoperitoneum. Splenic rupture.

Blood (arrow) surrounding the upper pole of the

spleen.

Spleen is heterogeneous in echotexture.

Splenic rupture is confirmed at operation.

Hemoperitoneum. Splenic rupture. Fluid surrounding

the spleen (arrows).

Hemoperitoneum. Splenic rupture. Blood

(arrow) surrounding the spleen. It is more fluid

in subdiaphragmatic space (between the spleen

and the diaphragm).

Wedge-shaped defect of the spleen is also

visualized.

Hemoperitonium. Splenic rupture.

Large amount of the blood surrounding the

spleen.

Hemoperitoneum – large amount of fluid (green arrow)

surrounding the spleen (S). Fluid outlines the

gastrosplenic ligament (blue arrow). Note the small bare

area of the spleen (black arrow).

Also left pleural effusion (yellow arrow) is seen above

the diaphragm (white arrow).

The example of splenic rupture Studies demonstrates that isolated left upper quadrant free fluid, in both upper quadrants, or

diffusely (fluid in LUQ, RUQ and pelvis) is significantly associated with splenic injuries. The

dynamics of flow in the abdomen are of interest in that free fluid tends to flow from the left to

the right upper quadrant rather than down the left paracolic gutter into the pelvis.

It can be explained that hemorrhage from the spleen first accumulates in the left and then flows

to the right upper quadrant because the phrenocolic ligament acts as a relative barrier to the

movement of fluid to the left gutter. Also fluid from the RUQ flows down via the right paracolic

gutter to pelvis rather than toward the left upper quadrant, perhaps because of the gravity

dependence of the right paracolic gutter and pelvis.

Splenic rupture. At examination of the left upper quadrant was

detected the spleen with markedly heterogeneous

parenchyma, surrounded by fluid (arrows).

Splenic rupture.

A large amount of a fluid at the lower edge of the

liver.

Splenic rupture. A fluid in the pouch of Morison.

Splenic rupture.

Longitudinal scanning of the suprapubic region.

Large amount of fluid in a pelvis (arrow).

UB - urinary bladder.

Look for fluid in left pleural cavity

At searching for left sided hemothorax the probe from splenorenal view should be angled more

cephalad for well visualization of the spleen and diaphragm and look for fluid above the

diaphragm.

The spleen is an acoustic window at examination of the left pleural cavity. Thus, the spleen,

diaphragm and the left pleural cavity which located over the diaphragm should be well

visualized.

Look for fluid in the left pleural cavity.

The probe from splenorenal view should be

angled with beam direction more cephalad

for well visualization of the spleen and

diaphragm and look for fluid above the

diaphragm.

But left pleural cavity view can be difficult to obtain and the probe should be angled or moved

with different positions (superiorly or inferiorly, anteriorly or posteriorly – depends from spleen

location) for obtaining the desired images.

Normally, mirror image of the spleen projected

above the diaphragm (because of a mirror artifact).

Sp – spleen

LK – left kidney

MI – mirror image

Diaphragm – (arrow).

At hemothorax this mirror artifact disappears, and replaces by anechoic space above the

diaphragm representing blood in the left pleural cavity.

Left-sided hemothorax – anechoic fluid above the

hyperechoic diaphragm (arrows)

S - spleen

Left-sided hemothorax - anechoic fluid above the

diaphragm .

S - spleen

PE – pleural effusion

РА - pulmonary atelectasis (collapsed lung) due to

a compression.

Look for free fluid in pelvis

Pelvis should be examined when the patient‟s bladder is full. Free fluid in the pelvis may be

missed if the patient has an empty bladder. The empty or partially filled bladder is the most

frequent cause of false-negative result. A full bladder act as an acoustic window to detect free

fluid in pelvis.

At full bladder its walls are well visualized. The bladder wall is anatomic landmark dividing a

fluid in a bladder and a free fluid in a pelvis, therefore searching for free fluid in a pelvis is

performing directly behind the bladder walls.

Small amount of free fluid in a pelvis accumulates in a pouch of Douglas in women (between the

uterus and rectum) and rectovesical pouch in men (between the bladder and rectum).

Larger amount of free fluid in a pelvis will surround a bladder. Need to obtain both transverse

and longitudinal images of the bladder with searching for free fluid just behind wall of the

bladder and in Douglas pouch or rectovesical pouch. Free fluid will usually appear as anechoic or hypoechoic, but may be hypoechoic with a few

internal echoes or echogenic if blood is clotted. Also in a fluid will be defined floating bowel

loops.

To obtain the suprapubic view, the probe should be placed just above the pubic symphysis and

directed inferiorly into the pelvis. As with all scanning applications, both transverse and

longitudinal planes are critical to fully evaluate the pelvis for fluid, as there are many imaging

artifacts and confusing structures that can confound the exam.

Suprapubic probe placement.

In the beginning the probe should be

placed in a transverse position on 2 cm

above pubis (for transverse imaging of the

bladder), then turn longitudinally (for

longitudinal imaging of the bladder).

Longitudinal view of the suprapubic region.

Free fluid in pelvis surrounding the wall of the urinary

bladder.

Free fluid – yellow arrow.

Bowel – green arrow.

The free fluid well outlines bowel loops which are

easily defined, peristalting and floating in anechoic

space.

Longitudinal view of the suprapubic region.

A large amount of slightly echogenic fluid in a

pelvis (clotted blood).

UB - Urinary Bladder.

Transverse view of the suprapubic region.

The minimal amount of free fluid in a pelvis.

Free fluid is noted by arrows as anechogenic space

just behind the bladder wall.

UB – Urinary Bladder.

Transverse view of the suprapubic region.

Free fluid in a pelvis (arrow) just above of the

bladder.

UB - Urinary Bladder.

At empty bladder the collection of a free fluid in the pelvis should not be mistaken for a bladder.

Unlike a urinary bladder where anechoic fluid is limited by walls, the free fluid outlines the

organs with sharp angles of fluid collections. If difficulties occurs in differentiation of a free

fluid from a bladder, the placement of a Foley catheter will help to identify the bladder.

Longitudinal view of the suprapubic region.

Normal rectovesical pouch (arrows), the space

between the rectum (R) and the urinary bladder

(UB) without free fluid. The fluid-distended

rectum should not be mistaken for free fluid.

Also transverse scanning can help to determine

that this structure is rectum.

Echogenic fluid or clot may be less obvious than the anechoic free fluid but should not be

overlooked.

Longitudinal view of the suprapubic region

reveals an isoechoic clot filling the cul de sac

(arrows).

Intraperitoneal clot is usually hyperechoic relative

to adjacent structures. Occasionally, however, it is

isoechoic, and intraperitoneal bleeding or

parenchymal injury may go unrecognized.

Familiarity with the typical appearance of the

peritoneal reflections and of the normal

configuration of the solid organs should improve

recognition of intraperitoneal clot.

Longitudinal view of the suprapubic region.

Normal appearance of the pouch of Douglas.

Absence of a free fluid (anechogenic space)

between a uterus and a rectum.

UB - Urinary Bladder.

Longitudinal view of the suprapubic region.

A small amount of free fluid in the pouch of

Douglas (anechoic fluid collection space

posterior to the uterus (arrow).

b - urinary bladder.

Longitudinal view of the suprapubic region.

Fluid in the pouch of Douglas, surrounding the

uterus (arrow).

Transverse view of the suprapubic region.

A transverse image of the uterus.

A large amount of free fluid in a pelvis (arrows)

surrounding uterus.

Any quantity of fluid is considered positive, except for anechoic fluid measuring less than 3 cm

in maximum antero-posterior dimension and isolated to the pelvic recesses in reproductive-age

women, is considered physiologic in the absence of other suspicious findings.

Clinical observation in such situations is usually enough.

Physiological fluid in a pelvis.

Longitudinal view of the suprapubic region shows a

small amount of free fluid in the pouch of Douglas

(arrow).

R – rectum.

U – uterus.

UB – urinary bladder.

If small amount of free fluid is detected in the pouch of Douglas which associated with fluid in

any other places is considered hemoperitoneum and usually indicates on clinically considerable

injuries.

After investigation upper quadrants and a pelvis should be quickly examined left and right

paracolic gutters, applying transverse scanning, especially when in upper quadrants and in a

pelvis the free fluid is not detected.

Paracolic gutters The paracolic gutters are additional sonographic views that may increase the sensitivity of the

standard FAST exam for the detection of peritoneal fluid. They are obtained by placing the

transducer in either upper quadrant in a coronal plane and then sliding it caudally from the

inferior pole of the kidney. Alternatively, the transducer can be placed in a transverse orientation.

The free in right paracolic gutter (yellow arrow) at the

transverse scanning.

Bowel loops (black arrow).

Also should be examined the central part of abdomen for detection of free fluid between bowel

loops, as indirect sign of bowel or mesentery injuries.

Quantity of free intraperitoneal fluid

The detectability of free fluid during the FAST examination is strongly dependent on the volume

of fluid present. The quantity of free intraperitoneal fluid that can accurately be detected on

ultrasound has been reported to be as little as 100 mL. The sensitivity of FAST increased with

larger volumes of free fluid.

The false-negative result is often caused by early performance of FAST protocol when

hemoperitoneum yet not reached detectable quantity.

Serial sonography may be useful for detecting free fluid in patients with BAT (Blunt Abdominal

Trauma). If there is active bleeding in the abdomen, the amount of fluid should increase with

time and would be more amenable to sonographic detection.

Studies demonstrates that the repeated sonographic examinations after 30 minutes and after 6

hours in hemodynamically stable patients with primary negative FAST, raises sensitivity of a

method.

Also, the use of ultrasound as a screening test for blunt abdominal trauma not only offers the

expeditious identification of hemoperitoneum but also allows for fluid quantification.

Increasingly recognized that hemoperitoneum following trauma is not necessarily an indication

for immediate laparotomy in stable patients. Quantifying free fluid during the early stages of

assessment may improve patient selection for laparotomy.

Although US can demonstrate the extent of hemoperitoneum, communication of this information

to the surgeon has been limited to the use of words such as "trace," "moderate," or "large" to

describe fluid volume. To improve information transfer and assist the surgeon in decision

making, a scoring system for fluid quantification was developed. Providing the surgeon with a

hemoperitoneum score will help in the decision-making process (conservative or operative

treatment).

Qualitative fluid scoring system is widely used. The higher the score, the higher the intra-

abdominal injury rate and the greater the need for surgery.

McKenney et al. proposed a hemoperitoneum scoring system based on the antero-posterior depth

of the largest fluid collection measured in centimeters plus one point for each additional area

with fluid.

The depth of the largest collection plus the total additional points given equals the patient‟s

hemoperitoneum score.

A score of greater than 3 is associated with an increased need for surgical intervention.

A score of less than 3 is more often do not need operative treatment.

Studies demonstrates that hemoperitoneum score is a more accurate predictor of the need for a

therapeutic operation than initial systolic blood pressure and base deficit. And it is especially

important when the unstable condition of the patient can be caused by other causes (orthopedic

or neurologic) at multiple injuries.

Calculation of the hemoperitoneum score.

28-year-old man after a motor vehicle crash.

A) Longitudinal sonogram of the pelvis shows

the largest collection of free fluid measured

10 cm from anterior to posterior (between

calipers).

UB – urinary bladder.

Subhepatic fluid and perisplenic fluid (B and

C) give two addition points, resulting in a

hemoperitoneum score of 12 (10 + 1 + 1).

B) Longitudinal US image of the Morison pouch

shows one additional site of fluid (asterisk).

C) Perisplenic fluid (asterisk), as second additional

site of fluid. Also heterogeneous splenic

parenchyma was detected.

Hemoperitoneum score 12 (10 + 1 + 1). Emergency

splenectomy was performed.

(A) Sonogram positive for fluid in the left upper

quadrant only. Transverse image of perisplenic

area shows 0.3 cm of fluid (arrow).

Hemoperitoneum score = 0.3.

(B) CT scan reveals a small splenic laceration

(arrow) that was managed nonoperatively.

Also in practice for detecting of hemoperitoneum volume other methods are applied.

Tiling considered a small anechoic stripe in Morison's pouch to represent about 250 mL

of fluid and a 0.5-cm anechoic stripe to correspond to more than 500 mL of fluid within

the peritoneum.

The free fluid revealed in 2 or 3 pockets, corresponds approximately to 1 L of the blood.

But decision for surgical intervention depends from all factors (results of sonography, СТ,

systolic BP, hematocrit, clinical data). Large amount of the free peritoneal fluid which detected at FAST examination is indication for

immediate laporotomy in patients with unstable hemodynamic without performing of CT. Small

amount of a fluid in patients with stable hemodynamic suspects a mild bleeding and in such

situations should be performed СТ, as definitive diagnostic test, which allows to diagnose not

only degree of rupture, but also presence of active bleeding at extravasation of contrast material.

Look for pneumothorax

Pneumothorax represents the second most common injury, after rib fracture, in blunt chest

trauma.

The diagnosis of traumatic PNX is suggested by clinical signs and is generally confirmed by

standard chest radiography, usually if pneumothorax is large. At obvious clinical signs of

massive pneumothorax emergency chest tube is placed without radiographic confirmation.

But a clinically silent (minimal, small) pneumothorax is difficult to diagnose by physical

examination or radiographically and it often remains undiagnosed.

The detection of an occult PNX is important, because small PNX may rapidly progress to tension

PTX if diagnosis is missed or delayed, especially in patients receiving mechanical ventilation.

PTX may increase the mortality rate in trauma patients if it is not promptly recognized.

Thorax radiography in trauma patient is usually performed in supine position. Up to 30% of

PNX are missed (occult pneumothorax) by the initial bedside antero-posterior supine chest

radiograph.

In the supine trauma patient without previous pleural disease, pathologic air within the pleural

space tends to rise to the anterior chest wall at the paracardiac regions and anterior costo-

diaphragmatic sulci. Therefore ultrasonography is ideal for detection of anterior pneumothorax.

US is more sensitive than supine chest radiography with sensitivity of 95%-100%) for PNX

detection, compared with the supine chest radiography (36%-75%).

Sometimes even massive pneumothorax can be not detected by radiography in the supine trauma

patient.

US is highly sensitive and also has a high negative predictive value for the detection of traumatic

pneumothorax and therefore can be an effective diagnostic tool to definitively exclude

pneumothoraces in trauma patients.

Value of ultrasonography in pneumothorax detection consists in its rapidity (providing diagnosis

within few minutes), especially at life-threatened conditions, such as tension pneumothorax,

there is no time for radiologic confirmation.

Also US can quickly exclude pneumothorax (skilled operators can exclude pneumothorax within

few seconds).

СТ has excellent diagnostic accuracy. СТ is the gold standard in pneumothorax detection and its

volume, however cannot be performed in patients with unstable haemodynamic.

Ultrasonography is especially useful in emergency diagnosis, in which no radiographic

equipment is readily available. It may occur in locations where access to traditional means of

diagnostic confirmation (CT and chest radiography) is not readily available, such as remote

military operations, space travel, and during natural disasters and mass-casualty situations.

Newly developed US equipment includes high-quality portable units that are easily transported

by hand. The use of these units can enable the assessment of thoracic trauma in many diverse

environments.

Therefore sonography has a number of advantages: highly sensitive, rapid and simple method at

performance and interpretation of results.

Technique

This technique is simple and for training only few examinations are required. Assessment of the

chest to rapidly confirming or rule out a pneumothorax is performed by the same abdominal

probe with frequency 3.5 - 5 MHz, but in presence of any doubts examination should be

performed with the linear high-frequency probe (7 - 10 MHz) for best visualization of sliding of

the visceral pleura.

Scanning should be performed with short depth (approximately 5 cm).

Anterior chest view for pneumothorax detection.

The transducer is placed longitudinally in the

midclavicular line usually over the third and

fourth intercostal spaces

The probe is placed perpendicular to the

ribs in the anterior chest region for

scanning 2-3 intercostals spaces in the

midclavicular line (usually 3 rd - 4th

intercostals spaces). If visualization is inadequate, the probe

can be rotated on 90 degrees, placing it

directly in intercostal space along ribs.

Need to obtain the cross-section image of 2 ribs with an

intercostal space between them.

This scan is classic at any investigations of the pleura and

lungs, because the hypoechoic ribs with posterior shadows

act as fixed anatomical landmarks for rapid detection of a

pleural line. Because pleural line is well defined as

hyperechoic stripe located just below ribs.

Ribs (yellow arrows) with clear acoustic shadowing.

The pleural line (green arrow), A - line.

The pleural line is border between soft tissue of a chest wall and a lung and represents the

parietal and visceral pleural interface.

Parietal pleura looks as hyperechoic line which located just below ribs and is motionless.

Visceral pleura covering a lung is located under parietal pleura and moves (to-and-fro),

synchronously with respiratory movements.

Pleural layers are accurately visualized with using high-

frequency transducer (10MHz).

The visceral pleura is separated from the parietal pleura by a

thin layer of pleural fluid in the pleural space.

1 - normal visceral pleura.

3 - normal parietal pleura representing thin echogenic line.

2 - pleural space representing anechoic or hypoechoic stripe

between parietal and visceral pleura.

The parietal pleura is well visualized

(arrow).

The visceral pleura (triangles) seems

thicker and more echogenic due to

reverberation artifacts on the visceral

pleura/air-filled lung interface and

consequently is easily visualized and

identified by its movement with respiration

(sliding sign). The attention should be

focused on searching of sliding movement

(to-and-fro) of the visceral pleura.

Should be investigated few respiratory

movements.

This sliding movement of the visceral pleura is called «lung sliding». If sliding movement is

revealed, pneumothorax is almost completely excluded. Absence of «lung sliding» is the basic

sign of a pneumothorax.

The normal to-and-fro sliding of the visceral pleura against the stationary parietal pleura is easily

visualized and is synchronized with respirations. Therefore visualization of the sliding shows

that visceral pleura is not separated from parietal pleura by air.

At pneumotorax «lung sliding» is absent, because a parietal and visceral pleura separated by air.

Therefore absence of the sliding indicates subparietal air collection.

Also, directly below this hyperechoic pleural line, hyperechoic vertical «comet tail» artifacts are

normally visualized, named B - lines. This is a reverberation artifact that has been described as a

vertical, narrow-based, echogenic band extending from the visceral pleura into the deeper

portions of the imagine (laser ray-like). This is generated by the large difference in impedance

between the pleura (highly reflective) and its surrounding air filled lungs. This arises from the

pleural line and fans out to the edge of the screen.

In the presence of a pneumothorax, these reverberation artifacts are absent due to separation

parietal and visceral pleura by air.

Normal lung.

B-lines vertical, comet-tail artifacts arising from the pleural line,

hyperechoic and long (spreading up to the edge of the screen). B-lines arise due to reverberation on interface between visceral

pleura and air in superficial alveoles of lung.

Therefore these linear artifacts also moves (to-and-fro) together with

a lung movements at inspiration and expiration, reminding a laser

beam.

At a normal lung comet-tail artifacts can be single or multiple, but less than 7 in one intercostal

space. Because significant amount of B - lines (7 and more) at a thorax trauma is a sign of a lung

contusion.

Normal lung.

Single vertical «comet tail» artifact (B line).

In real time moves «to-and-fro», synchronously

with «lung sliding», reminding a laser beam.

Lung contusion at a trauma.

In this example the lung contusion is

represented by alveolar-interstitial syndrome

(AIS) and sonogram shows multiple (7) B

lines originating from a pleural line.

Short distances between vertical linear

artifacts indicates their large quantity.

The diagnosis of pneumothorax relies on the “absence” of both the normal lung slide as well as

the normal of comet-tail artifacts. The one study demonstrates that combining the absence of

normal lung sliding and comet-tail artifacts has a sensitivity of 100% and a specificity of 96%.

Therefore the sonographic diagnosis of the pneumothorax is based on the basic signs: absence of

"lung sliding» and absence of vertical artifacts (B lines). And in the presence of these signs

pneumothorax is almost completely excluded.

Also at pneumothorax present the rough, multiple horizontal artifacts originating from the

pleural line (A - line). These horizontal repetitive artifacts are called A - lines.

Normally, one or more horizontal artifacts also can be visualized, but they are usually subtle and

distance between repetitive A-lines strictly equal to distance from a skin to the pleural line

because they are reverberation artifacts from ultrasound reflection between these two surfaces.

Sometimes, normal A-lines can be rough, multiple similar to pneumothorax pattern, but presence

of the lung sliding helps to exclude pneumothorax in such situations. So, A lines itself can be

less helpful.

Imaging of the normal lung. The arrows show the pleural line.

Normal horizontal artifacts (A) are shown (A-lines). Ribs

(asterisks).

A (normal lung B-mode) – presence of

lung sliding (in real time) with few

subtle horizontal artifacts which are

parallel to A - line. Their depth is

a multiplicative of the distance between

the skin surface and the pleural line.

B (pneumothorax b-mode) – absence of

lung sliding (in real time) with multiples,

rough horizontal artifacts which are

parallel to A - line.

In doubtful cases comparison with opposite hemithorax can help to diagnose pneumothorax

(if bilateral pneumothorax is not present).

Usually B-mode examination is enough for confirmation or rule out pneumothorax, but lung

sliding sometimes can be subtle, therefore in doubtful cases should be performed M-mode.

In the M-mode presence of sliding characterized by a “seashore sign”, which included

motionless parietal tissue over the pleural line and a homogenous granular pattern below it.

Normal lung (M – mode)

Parallel lines above the pleural line (arrows) representing the

motionless parietal tissue of the chest wall (reminds the sea with

silent waves).

Below the pleural line a homogenous granular pattern

representing the constant motion of the underlying lung and

giving the appearance of a sandy beach.

This pattern known as the «Seashore Sign».

This phenomenon, known as the “Seashore Sign” indicates

normal lung sliding and excludes pneumothorax.

Normal US lung imaging in M-mode

(left) and B-mode (right).

M-mode image demonstrates linear,

laminar pattern in the tissue

superficial to the pleural line (arrow)

and a granular or “sandy” appearance

deep to the pleural line (“Seashore

Sign”).

Normally, few subtle horizontal

artifacts which are parallel to pleural

line also visualized.

In the case of a pneumothorax, normal sliding is absent and M-mode reveals a series of parallel

horizontal lines, suggesting complete lack of movement both over and under the pleural line.

This is known as the “Barcode sign”.

M-mode image demonstrates linear,

laminar pattern in the tissue superficial to

the pleural line (arrow) and a similar linear

pattern deep to the pleural line.

This phenomenon, known as the «Barcode

sign» indicates absent lung sliding and

means the presence of pneumothorax.

Comparison of the M -mode images of the normal lung sliding

with a phenomenon of «Seashore Sign» and pneumothorax with

a phenomenon «Barcode sign».

Also a Рower Doppler can be used for enhancement of recognition of lung sliding.

Presence or absence of Рower Doppler signals can exclude or confirm pneumothorax, because

Power Doppler is very sensitive to movement.

Presence of Рower Doppler signals at the pleural interface reflects respiratory movements of a

lung along a pleural surface and can enhance the recognition of lung sliding. Color enhancement

of the pleural line sliding with respiration is known as the «power slide».

At examination the probe should be motionless for excluding the artifacts caused by movements

of the probe, which should not be mistaken for «power slide» signals.

Power Doppler of normal lung sliding.

Color Power Doppler image illustrating the presence of

movement at the pleural line (power slide) – thus

confirming lung sliding and excludes pneumothorax.

The color gain is low so that only movement along the

pleural interface is demonstrated. Avoid setting the gain

too high, as general patient respiratory motion will be

detected.

Pneumothorax.

No power Doppler signals at the pleural interface (absence

“power slide”) confirms pneumothorax.

The gain adjusted correctly by comparison to the normal left

hemithorax

But all described above signs are indicated only on presence of pneumothorax but not about its

size. Also these signs of pneumothorax do not have 100 % specificity because absence of "lung

sliding» which is specific for pneumothorax, can occur at other conditions such as main stem

intubation (usually the right main stem) with absence of the «lung sliding» on the opposite side,

pleural adherences, bullous emphysema and advanced chronic obstructive pulmonary disease,

bronchial asthma, respiratory distress syndrome, so lung sliding can be abolished in the absence

of pneumothorax. Though, in a trauma context pneumothorax is most probable if the patient had

no previous lung disease.

Therefore numerous researches was performed for detection of the most specific sign of

pneumothorax and determination of its size by ultrasonography. It was revealed that such sign is “Lung Point”. “Lung Point” is highly specific sign of

pneumothorax (specificity 100 %).

This sign is used for confirmation of the pneumothorax and also for determination of the its size

(small, moderate, massive). Information about size of the pneumothorax is important for clinical

decision in the management of the pneumothorax (the drainage is necessary or not).

СТ - is gold standard for detection of the pneumothorax and its size.

Earlier was considered that ultrasonography is a high-sensitive method for detection of the

pneumothorax, but is unable to determine its volume. But the subsequent studies have overturned

this viewpoint and recent studies shows, that localization “lung points” where lung sliding and

absent lung sliding appear alternately, allows to determination of the size of pneumothorax with

the accuracy similar to accuracy at СТ.

For determination of the size of pneumothorax examination should be extended to lateral regions

of the chest wall for detection of the point where the normal lung pattern (lung sliding with

vertical B-lines) replaces the pneumothorax pattern (absent lung sliding and horizontal A-lines).

This point is called the “Lung Point” and is border of pneumothorax.

Diagram explaining the origin of the “Lung

Point”.

At partial pneumothorax with an incomplete lung

collapse, in this place, parietal and visceral

pleura are separated by air with pneumothorax

pattern (absent lung sliding) while in other part

pleural layers are not separated by air with

normal sliding pattern .

The lung point is found at the site where partially

collapsed lung is apposed to the inside of the

chest wall. With careful technique, the examiner

searches for the site at which the two pleural

surfaces touch.

For detection of lung point the probe is moved

from anterior to lateral regions of the chest wall.

At the border of pneumothorax pleural layers

start to contact during inspiration (lung itself is

located in front of the probe, which remained

motionless at the site of examination) with

normal lung sliding. And during expiration

pleural layers are separated again.

“Lung point” is visualized only in real time there B-mode

signs of pneumothorax start to disappear during inspiration

with fleeting appearance of pleural sliding at the examination

of lateral regions of the chest wall (alternating pattern of

pneumothorax with normal lung sliding in this boundary

region).

“Lung Point” usually is well visualized in B-mode, but this sign can be confirmed or facilitate its

detection, using the M-mode. Applying the M-mode, the probe must be placed motionlessly at

the site of examination. On the M-image in this site will be detected alternating pattern of

“Seashore sign” during inspiration with “Barcode sign” during expiration.

Alternating pattern of “Seashore sign” with

“Barcode sign”.

M - mode image demonstrates an alternating

pattern of pneumothorax “Barcode sign”

with normal lung sliding “Seashore sign”.

This occurs at the boundary of the

pneumothorax where lung sliding is appears

during inspiration and disappears during

expiration.

This phenomenon, known as “Lung point”,

confirms the presence of pneumotorax with

determination its border.

Look for pneumothorax and its size should be performed with “two-look approach”.

The “first look” consists of anterior chest wall examination in standard points (longitudinal

scanning of the anterior chest wall in 3 - 4 intercostal spaces on mid-clavicular line).

If pneumothorax pattern is detected, a “second-look” should be performed. The probe should be

moved laterally along the chest wall and systematically assessed with transverse scans along the

intercostal spaces from midclavicular (or parasternal) line to mid-axillary line to evaluate its size

and location.

This technique attempts to identify the lateral extent of the pneumothorax by localizing the

“Lung point” – point of chest wall where pneumathorax pattern (absent lung sliding) alternating

with the normal lung pattern (normal lung sliding).

The search for the lung points (lateral limit of the retroparietal air collection) is followed through

three intercostal spaces (second or third, fourth or fifth, and sixth or seventh, respectively defined

as high, medium, and low sectors).

“Lung point” detection (size of

pneumothorax).

Intercostal spaces should be

systematically assessed from anterior to

lateral parts of chest wall on the side of

pneumothorax or bilaterally, if bilateral

pneumothorax is present.

Appearance of lung sliding at inspiration indicates contact of visceral and parietal pleura in this

place. So, the “Lung point” marks the periphery of the pleural air collection in this point.

When the patient is upright, the air collects in the apicolateral location. In fact, when the

patient is in the supine position, air in the pleural space collects anteriorly and inferiorly within

the anteromedial and costophrenic regions of the pleural spaces.

For physical reasons, the detection of the absence of sliding sign in the supine patient with PNX

is more successful anteriorly in the parasternal line and near the diaphragm (“deep sulcus sign”

area).

The finding of an immobile pleural line in the “deep sulcus sign” area allows the diagnosis of

PNX, whereas the systematic research of the lung points permits the evaluation of its extent and

consequently the hypothesis of its radiographic visibility. The sonographic findings of PNX in the “deep sulcus sign” area are defined as the

“ultrasonographic deep sulcus sign”. The “deep sulcus area” is the anterior thoracic area

corresponding to the projection of the cardiomediastinal borders and anterior costophrenic

sulcus, bounded superiorly by the second rib, inferiorly by the diaphragm and laterally by the

mammary lines above and the anterior axillary lines below.

Anatomical projection of the “deep sulcus sign” on anterior

chest wall.

“deep sulcus area” (blue area).

Anatomical structure – air collecting in antideclive

pleural space (PNX, occult)

The correct position of probe during the examination is

indicated. The first look is conducted by moving the probe in a

longitudinal scan starting from the parasternal line (or

midclavicular line): this approach provides to detect or rule

out PNX. The second look is conducted by directly exploring

the intercostal spaces accurately to recognize the lung point:

its aim is to evaluate the size and location of PNX and to

delimit the deep sulcus area.

In the supine patient with small pneumotorax pleural air is occupied anterior aspects of chest

(anterior pneumothorax), while at a large pneumothorax pleural air is extended laterally

(anterolateral pneumothorax).

PNXs are classified on CT images, according to Wolfman et al. (1993), as “anterior” (anterior

pleural air not extending to the mid-axillary line dividing the thorax into equal anterior and

posterior halves) or “anterolateral” (pleural air extending at least to the mid-axillary line).

Studies shows that anterior lung point is correlated with minimal and generally radio-occult

pneumothorax. The more lateral the lung point, the more the pneumothorax is substantial.

Major pneumothorax yields very posterior or absent lung point (if total collapse of lung is

present).

Anterior PNXs do not requires a drainage, while anteriolateral pneumothoraxes requires a

drainage.

Anterior PTX.

Pen-mark delimitation of retroparietal air

collection.

MCL – mid-coronal line

Anterior PTX on CT scan with delimitation (arrow).

Pleural air does not extend to the MCL - mid-coronal

line (red line).

MCL (mid-coronal line) – defined as the line that

divides the thorax into equal anterior and posterior

halves.

For detection of the size of pneumothorax time is required (about 3 minutes at investigation of

one hemithorax), so should be performed only in patients with stable haemodynamic, if time

permits.

If time is limited, it is possible to apply a method of rapid confirmation or rule out a large

pneumothorax. After detection of pneumothorax on anterior chest wall in standard points on

mid-clavicular line, should be investigated intercostal spaces on a mid-axillary line (from 5th to

8th), placing the probe also longitudinally for obtaining transverse scan of the intercostal spaces.

Absence of "lung sliding» and vertical artifacts (B-lines) with presence of multiple horizontal

artefacts at this place indicates large pneumothorax.

But in clinically obvious massive pneumothorax decompression by chest tube placement must be

performed promptly.

Subcutaneous emphysema

Diffuse subcutaneous emphysema can make visualization of the underlying pleural line

impossible, also interfering with ultrasound diagnostic ability. However, the pressure of the

probe can drive away air in some cases.

This potential pitfall is relatively unimportant in the unstable patient, as subcutaneous

emphysema equates to an underlying post-traumatic pneumothorax.

Artifacts at subcutaneous emphysema (Е – lines) are vertical “comet-tail” artifacts -

hyperechoic lines, spreading up to the edge of the screen and very similar to B-lines.

But Е – lines are originated from layers above a pleural line and distributed chaotic (from

various levels in soft tissue).

Subcutaneous emphysema.

Multiple chaotic subcutaneous hyperechoic

reflexions representing chaotic distribution of air

bubbles in soft tissues.

Subcutaneous emphysema.

Е - lines are vertical long hyperechoic lines,

spreading up to the edge of the screen and

originates from layers above a pleural line and

distributed chaotic, not from one line.

Unlike B – lines, which are originated from a

pleural line.

Searching for ribs in such situation can help to avoid this pitfall because of the pleural line is

located just below ribs. Therefore, if linear artifacts originates above this level (lack the

characteristic rib shadowing above) and are distributed chaotically it indicates a subcutaneous

emphysema.

Diagnostic signs of pneumothorax

o Absence of “lung sliding” o Absence of vertical artifacts

o Rough repetitive horizontal artifacts

o “Lung point”

Studies demonstrates that US is highly sensitive and has a high negative predictive value for the

detection of traumatic pneumothorax and therefore can be an effective diagnostic tool to

definitively exclude pneumothoraces in trauma patients.

It is rare that air does not migrate in the paracardiac regions and in the anterior

costodiaphragmatic sulcuses, as in the case of pleural adherences from previous disease

(posterior pneumothorax, apical septate, аnterior septate can be present in such cases).

Look for fluid in pericardium

Cardiac injuries more often occurs at penetrating trauma, than at blunt trauma.

Penetrating injuries to the heart have a high mortality, with more than 75%

dying before reaching the hospital. In those patients reaching the hospital, stab wounds

has a considerably higher survival rate (65%) than gunshot wounds (16%).

Though heart ruptures at blunt cardiac injuries occurs rarely, but mortality from these damages is

very high. The majority of these patients die prior to reaching the hospital.

Of those reaching the emergency department, right atrial rupture is the most common finding.

One third will have multiple chamber involvement, which is almost always fatal.

The mechanism of death is usually tamponade. Rapid diagnosis followed by early definitive

treatment. Therefore rapid detection of the pericardial fluid as indirect confirmation of heart

rupture, has huge value in patient survival.

Subxiphoid pericardial window has been considered the gold standard for the diagnosis

of these injuries and should be performed as soon as possible after patient arrival. A positive

exam would mandate immediate surgical intervention. Interval from positive diagnosis to the

operating room have approximately 12 minutes.

Ultrasonography can provide a significant amount of the information about heart, but a main

goal of FAST examination is identifying the presence or absence of pericardial fluid.

In a positive exam, one will see anechoic space (collection of fluid) between the heart and the

pericardium

If present pericardial fluid it is need to estimate its quantity and presence or absence signs of

tamponade. A positive exam would mandate immediate surgical intervention, but tamponade of

the heart is most frequent cause of death at traumatic cardiac injuries and emergency punction of

a pericardium and blood evacuation is required.

Pericardiocentesis is performed under permanent ultrasound guidance, usually from subcostal

access, but it can be performed from parasternal or apical access depending on localization of the

maximum quantity of fluid and better access. Evacuation even insignificant volume of blood

(even 30 ml) can considerably improve a hemodynamic situation. The quantity of the pericardial fluid can be estimated by measuring of width of the maximum

pericardial layers separation (anechoic space between heart and pericardium) at end-diastole. But

in critical situations its quantity is usually defined by visual assessment.

pericardial space separation

Mild Moderate Large

< 1 cm 1 – 2 cm > 2 cm

(100 – 250 ml) (250 – 500 ml) (> 500 ml)

Size is far less important than whether there are signs of tamponade.

Acute small pericardial effusion can result in tamponade if rapidly accumulated (this is true

especially for traumatic or iatrogenic tamponade) while moderate and even large pericardial

effusion, which accumulated gradually, can not cause considerable hemodynamic effects.

.

Tamponade

The normal pressure within the pericardium is zero or negative. As the amount of fluid in the

pericardium increases, the pressure rises. This increase in pressure does not allow complete

relaxation of the ventricles during diastole, and filling is reduced. The pressure is at maximum

during diastole and the ventricles may collapse. The right ventricle is typically affected, as it is

usually at a lower pressure than the left ventricle. Because the right ventricle is impaired, there is

a reduced cardiac output from the entire heart, leading to a drop in blood pressure.

Echocardiographic evidence of tamponade

diastolic RV collapse and/or RA collapse

Dilated IVC (>2 cm) with inspiratory collapse of <50%

Increasing of respiratory variations (>25%) of the transtricuspidal and transmitral flows at

Doppler study.

Intrapericardial pressure is maximal during diastole and cardiac chambers can collapse.

Echocardiographic part of FAST protocol is focused on the searching of any invaginations of the

cardiac chambers during diastole, mainly of the right chambers (right ventricle and/or the right

atrium). The collapse of the left chambers occurs much less often because of more pressure and

thicker wall, than in the right chambers, therefore the right chambers of the heart collapses first.

Right Atrial Collapse.

Due to thin walls and low intracavitary pressures, the right atrium is the first cavity to be

compressed with fluid accumulation in the pericardial sac. As such, right atrial collapse

(inversion, invagination) is a highly sensitive sign, picking up even minimal elevations in the

intrapericardial pressure. However, since it has also been described in patients with small

pericardial effusion and no hemodynamic confirmation of tamponade, its specificity for clinical

use is low (50 - 68 %), especially as an isolated finding.

Diastolic Right Ventricular Collapse.

Diastolic RV collapse occurs with further elevation of intrapericardial pressures. Thus, it is a

more specific sign (84 – 100%), than right atrial collapse, while having a good sensitivity and

signaling a more advanced degree of hemodynamic compromise, however is more late sign of

tamponade.

The collapse of the left chambers of the heart occurs much less often (25 %) and is highly

specific a sign, but a late sign of tamponade.

Diastolic collapse of the right chambers of the

heart.

The most important echocardiographic

indicators of hemodynamic significant

pericardial effusion are Diastolic Right

Ventricular Collapse (movement of the free wall

of the right ventricle inside during diastole)

and/or Right Atrial Collapse (movement of a

free wall of the right atrium inside during

diastole).

Dilated IVC (>2 cm) with inspiratory collapse of <50%.

Inferior vena cava plethora with decreased respiratory variations indicates high right atrial

pressure.

Absence or insufficient collapse the IVC at inspiration is a highly sensitive sign of tamponade.

At tamponade the IVC is dilated (> 2 cm), without change in diameter or insignificant reduction

of its size at inspiration (with inspiratory collapse less than 50%). Normally, the size of the vena

cava decreases at inspiration more than 50 % (well collapsed IVC).

IVC during inspiration and expiration using M

mode. Measurement B shows the inspiratory

IVC diameter as compared to expiratory

diameters A and C.

Subcostal view showing a dilated (2.5 cm) inferior

vena cava without any change in diameter during

respiration, indicative of elevated right atrium

pressure.

This “flat” pattern can be visually identified in the

two-dimensional image and clearly checked on the M-

mode scan.

But the most specific echocardiographic sign of tamponade is abnormally increased respiratory

variation in transvalvular blood flow velocities. Normally, inspiration causes a minimal increase in tricuspid and pulmonary valvular blood flow

and a corresponding decrease in mitral and aortic flow velocities.

Thus, in a normal subject, inspiratory variations are less than 20% and are almost invisible. With

cardiac tamponade, ventricular interdependence is exaggerated, and respiratory variation

is abnormally increased (more than 25 %).

The pulsed wave Doppler study of the transmitral

flow shows a marked respiratory variation (which is

known as "sonographic pulsus paradoxus")

consistent with tamponade physiology .

At inspiration transmitral flow velocity (peak E) is

considerably decreased (respiratory variation more

than 25 %).

(also transtricuspidal flow velocity will increase at

inspiration with respiratory variation more than

25%).

But in critical situations is no time for performing of classic investigation, therefore at the

presence of the pericardial fluid during FAST examination need searching for right chambers

diastolic collapse only, confirming tamponade.

In general, tamponade is not a subtle finding and should be suspected by the presence of a

moderate to large pericardial effusion and hemodynamic instability.

Necessary to remember that tamponade of the heart is the clinical diagnosis. Therefore at the

presence of the pericardial fluid with clinical signs of tamponade not always can be present

diastolic collapse of the right chambers of the heart due to difficult interaction of the factors

influencing on haemodynamic effects at pericardial effusion (pericardial relations of volume-

pressure, speed of accumulation of a fluid and the volume status).

Also at the presence of the collapsed right chambers of heart can be no clinical signs of

tamponade. In such situations collapsed right chambers of the heart is the indicator of

haemodynamically significant pericardial effusion and it considered as threatened tamponade.

Technique of searching pericardial fluid

The subxiphoid pericardial view

(Subcostal View). Looks for blood in

the pericardial sac and tamponade.

Subcostal View

The patient is supine.

The transducer is placed just below the

xiphoid process and directed toward the

left shoulder in a horizontal plane.

Pivot, sweep, and tilt the transducer to

view all four cardiac chambers.

Identify the heart, four cardiac chambers,

and surrounding pericardium.

Subcostal View

Visualized all 4 chambers of heart.

RV - Right ventricle

RA - Right atrium

LV - Left ventricle

LA - Left atrium

The right chambers are closest to the

transducer and so appear more

anteriorly within the imaging sector.

Scan pearls and pitfalls

o Start imaging with the depth/scale setting at its maximum (e.g., 20 to 24 cm). This

should allow you to image the anterior and posterior pericardium in your initial

view. Gradually decrease the depth/scale (e.g., 14 to 18 cm) to fill the entire

sector image with the heart as you continue to optimize your image.

o The image must be closely scrutinized to ensure that the heart border and

pericardium are clearly identified

o A frequent mistake in imaging is to direct the transducer toward the spine rather

than coronally to the shoulder. You will often require less than a 30 degree angle

between the transducer and the skin.

o When your view is obscured by gas, slide the transducer slightly to the patient's

right subcostal region, using the liver as an echogenic window.

o If you are unable to view the heart in the subcostal window, move to a parasternal

long axis view.

o Clotted blood in the pericardium may not be as obvious as unclotted blood as the

contrast between ventricle and blood is reduced. This could lead to a false

negative result.

Subcostal four-chamber view.

The liver is used as ultrasound window through

which to view the heart.

Image of normal heart without pericardial fluid

(no anechoic space surrounding heart).

A pericardial effusion is visualized as anechoic or dark stripe between the (moving) walls of the

heart and the bright pericardium due to separation of the pericardial layers by streaming blood at

heart ruptures.

Also at ultrasound investigation sometimes can be identified site of the ruptured myocardium.

Transthoracic apical four-chamber view demonstrating

incomplete transverse tear (arrow) of the interventricular

septum. This image was obtained from a 50-year-old

man involved in a motor vehicle crash into a tree.

Hemopericardium.

Mild pericardial fluid is identified as an anechoic

stripe surrounding the heart within the parietal and

visceral layers of the bright hyperechoic pericardial

sac.

Haemopericardium (the pericardial fluid in a trauma context) will looks anechoic or dark, but

occasionally internal echoes representing fibrin, clot, or cardiac tissue may be present in

pericardial fluid.

Subcostal four-chamber view. Clot in the pericardial

space.

Subcostal view. Tamponade. A significant amount of the pericardial fluid (asterisks)

with a collapse of the free wall of right ventricle. Invagination of the right ventricular wall inside during

diastole (arrow).

The fluid collection in a pericardium can sometimes be localized. The localized compression of

heart can cause dramatic hemodynamic effects.

Subcostal view.

The large localized pericardial fluid collection (arrow)

with almost complete compression of the right ventricle

(triangles).

LV - left ventricle.

RA - right atrium.

If technically impossible to obtain adequate subcostal scan quickly due to narrow subcostal

space, obesity, gas or pain and also in pregnant women, the transducer must be moved to

parasternal view immediately, without wasting time.

Parasternal view.

Some specialists use parasternal view, as initial window,

because this access quickly allows to estimate a

pericardial space, as well as subcostal access or even

better.

But left-sided pneumothorax or large hemothorax can cause difficulties in heart visualization

from parasternal view or apical view, therefore in such cases subcostal view will be ideal.

Parasternal Long-Axis View (PLAX)

(a sagittal image through the heart)

The transducer is placed in the fourth or fifth left

parasternal intercostal space (just left of the sternum) with

the transducer indicator directed at the right clavicle or

shoulder.

If a given view is difficult to obtain, try sliding the probe cephalad or caudad one interspace or

toward the sternum or midclavicular line.

Parasternal Long-Axis View.

In this position should be visualized:

LV – left ventricle

RV – right ventricle

Ao – aorta

LA – left atrium

Aortic and mitral valves

The right ventricle is displayed at the top and the

left cardiac structures below.

The FAST examination is focused only on

detection pericardial fluid (anechoic space

surrounding ventricular walls).

Parasternal Long-Axis View.

The image of normal heart, absence of the pericardial

fluid behind the ventricular walls.

Parasternal Long-Axis View.

A significant amount of pericardial fluid

surrounding heart.

Excessive cardiac motion up to the “swinging

heart” is frequently seen in severe pericardial

effusion.

Parasternal Long-Axis View.

Tamponade (significant amount of pericardial fluid with

RV diastolic collapse).

РЕ - pericardial fluid, surrounding heart.

RV diastolic collapse (arrow )

The fluid is more surrounding a RV wall than a LV wall.

Parasternal Long-Axis View.

Tamponade (a significant amount of pericardial

fluid with RV diastolic collapse).

Рericardial fluid surrounding heart (asterisks)

RV diastolic collapse (arrow )

The fluid is more surrounding a LV wall than a

RV wall.

Pitfalls

A pericardial fat can be hypoechoic or contain grey level echoes, but usually have anecoic

appearance similar to a pericardial fluid and should not be mistaken for pericardial fluid.

However, the pericardial fat is almost always located anterior to the right ventricle and is not

present posterior to the left ventricle.

The Parasternal Long-Axis View is ideal to distinguish a pericardial fluid from anterior

pericardial fat. In the beginning fluid is accumulated behind a posterior wall of the left ventricle (due to

gravitation). If amount of the fluid reaches about 100 ml it starts to surround heart, filling all

pericardial space.

So isolated anechogenic space anterior to the right ventricle is pericardial fat and should not be

confused with pericardial fluid.

In Parasternal Long-Axis View is well visualized pericardial fluid behind a posterior wall of the

left ventricle, even insignificant amount.

Therefore, if at Parasternal Long-Axis View visualized anechoic space anterior to the right

ventricle without of the anechoic space (fluid) behind a posterior wall of the left ventricle it

represents pericardial fat.

If the anechoic space is visualized behind a posterior wall of the left ventricle it represents

pericardial fluid.

At M-mode using through the left ventricle also well visualized anechoic zone behind the left

ventricle (a small amount of fluid (<5 mm) may be present within the dependent pericardium,

but is usually considered to be physiologic when it is visualized during systole only).

Parasternal Long-Axis View. The anechoic space anterior to the right ventricle (white

arrow) without visualization of the anechoic space

behind a posterior wall of the left ventricle (yellow

arrow) represents pericardial fat.

Though the localized collection of a fluid only anterior to the right ventricle sometimes can

occurs.

The most frequent false-positive result at performing the FAST exam by not skilled

sonographers or emergency physicians is detection of the anechoic space anterior to the right

ventricle in the Subcostal View.

Subcostal View. The anehoic space anterior to the right ventricle

(yellow arrow) with absence of the anehoic space

behind a lateral wall of the left ventricle (green

arrow) is a frequent normal appearance

representing pericardial fat.

For error excluding (at any doubt) should be applied the alternative window (Parasternal Long-

Axis View ) in which absence of the fluid behind a posterior wall of the left ventricle excludes

pericardial effusion and confirms pericardial fat.

Also Parasternal Long-Axis View is ideal for confirmation of the presence of pericardial

effusion, detecting in subcostal positions, especially in doubtful cases.

At subcostal window is visualized pericardial

fluid surrounding heart (arrows).

The pericardial fluid was confirmed at

Parasternal Long-Axis View.

Fluid behind a posterior wall of the left

ventricle strongly confirms presence of fluid in

pericardium.

Also in Parasternal Long-Axis View the left sided pleural effusion can be visualized.

A left-sided pleural effusion can have a very similar appearance to that of a pericardial effusion.

Differentiation is by the location of the fluid relative to the aorta. On the parasternal long axis

view a pericardial effusion will finish just anterior to the descending aorta. A pleural effusion

will lie posterior to the aorta. If pericardial and pleural effusions exist side by side, the interface

of the layers will be visible.

Parasternal Long-Axis View.

Pericardial and pleural effusions

exist side by side.

The interface of the layers is

visualized as hyperechogenic

strip.

PE - pericardial effusion is

finished just anterior to the

descending aorta (Dao).

PL- pleural effusion (the

presence of the fluid posterior to

the descending aorta)

Lung can often be demonstrated within a pleural effusion.

At a significant amount of pericardial fluid heart will seem floating while in the presence of a

pleural fluid heart will seem fixed.

Also application of the alternative ultrasound scan can help to differentiate pericardial fluid from

the pleural fluid.

Alternative windows At the FAST protocol usually Subcostal View or Parasternal Long-Axis View is used, but in any

cases of doubt alternative windows should be performed such as Parasternal Short-Axis View

and Apical View.

Parasternal Short-Axis View.

The parasternal position of the short axis of the heart

is perpendicular to parasternal positions of the

longitudinal axis of the heart.

Parasternal Short-Axis View.

From the parasternal long-axis position, rotate

the transducer 90 degrees clockwise (to the

patient's left) or place the transducer in the

fourth or fifth left parasternal intercostal space

in a line connecting the left clavicle/shoulder

and the right hip.

A cross-section of the heart will be received at

the level of the aortic valve (base of the heart).

Slightly tilting the plane of the ultrasound beam

caudally with a beam direction to a heart apex

will be received cross-section scans of the heart

(from the base of the heart to the apex).

At the FAST examination parasternal short-axis view is usually obtained with the image plane at

the level of the mitral valve or papillary muscles.

Parasternal Short-Axis View.

Cross-section scan of the normal heart at the

level of the mitral valve. The motion of the

mitral valve resembles the mouth of a fish as it

opens.

No pericardial fluid surrounding ventricles.

LV – left ventricle (circular)

RV – right ventricle (crescent-shaped)

Parasternal Short-Axis View at the level

of the papillary muscles.

Identify the left ventricle (circular), right

ventricle (crescent-shaped), and

surrounding pericardium.

At the presence of pericardial fluid

anechoic space will be surrounded

ventricles.

LV – left ventricle

RV – right ventricle

Parasternal Short-Axis View.

Cross-section scan of the normal heart at the

level of the papillary muscles.

No pericardial fluid surrounding ventricle.

LV – left ventricle (circular)

RV – right ventricle (crescent-shaped), and

pericardium

Parasternal Short-Axis View at the level of the

papillary muscles.

A significant amount of the pericardial fluid (РЕ)

surrounding heart.

Parasternal Short-Axis

View.

Tamponade.

A significant amount of

the pericardial fluid with

diastolic collapse of the

free right ventricular wall

(arrow), the collapse is

observed in early diastole.

РЕ – pericardial effusion.

Parasternal Short-Axis View

at level of the aortic valve

(Ao)

The diastolic compression

of the outflow tract of the

right ventricle.

Apical Four-Chamber View (A4C)

Apical View also can be used as alternative window at the FAST examination for detection of

pericardial fluid.

Apical Four-Chamber View (A4C)

The transducer is placed over the cardiac apex

with the beam directed toward the right

clavicle/shoulder in a plane coronal to the heart.

The transducer indicator is directed toward the

left axilla.

Identify the left ventricle, right ventricle, left

atrium, right atrium, and surrounding

pericardium.

Apical Four-Chamber View.

Visualized all 4 chambers of the heart.

RV - Right ventricle

RA - Right atrium

LV - Left ventricle

LA - Left atrium

The upper half of the image shows

both ventricles, beneath them are

the right and left atria. The ventricles

and atria are separated by the mitral

and tricuspid valves.

The septal wall is in the center.

Normal Apical Four-Chamber View.

All 4 chambers of heart without pericardial effusion

are visualized.

Apical Four-Chamber View.

Tamponade.

A significant amount of pericardial fluids

(asterisk) with a collapse (invagination) of a

free wall of the right atrium (arrow).

Collapsed the right atrium is reduced in size

(RA).

Apical Four-Chamber View.

Tamponade.

The marked collapse of the wall of right

atrium (arrow).

Collapsed small the right atrium (point). A significant amount of pericardial effusion

(РЕ).

Except searching of a compression of cardiac chambers, also need looking for echoic structures

in pericardial cavity, represented by blood clots.

Apical a four-chamber view.

Large echogenic intrapericardial hematoma in the

areas of the right chambers of the heart.

The right chambers of the heart are small due to

compression.

Pericardiocentesis

Pericardiocentesis should be echocardiographic guided. Echo scanning allows the examiner to

detect the largest collection of pericardial fluid in closest proximity to the transducer, thereby

identifying the ideal entry site and so different approach is used to identify the area where the

pericardial space is widest and closest to the chest wall and perform the tap at that site.

Parasternal and apical approach may be used, which involves a more direct anatomic approach to

the heart than the subxiphoid approach. Excellent results are reported with this method, the

parasternal and apical windows being by far the most frequently used.

At subcostal approach the needle oriented in the general direction of the left shoulder. Imaging

from the subxyphoid area with the transducer draped in a sterile cover will confirm the best

direction for the largest pericardial space from this position, while at the same time avoiding a

transhepatic tract. The distance from the skin to the pericardium and the orientation of the

transducer should be mentally noted and the needle should be inserted as attempting to prolong

the central axis of the transducer. A good technique is to position a finger parallel to the

transducer and then use it to guide the needle. When a needle tip reached pericardial fluids the

second operator aspirated blood by syringe while the first operator strictly supports needle

position under constant ultrasound control on the monitor.

Echocardiographic guided

pericardiocentesis using subcostal

access.

In the given example the needle is

completely visualised in the liver

parenchyma at a puncture of the

pericardial cavity.

Direct transthoracal access using parasternal

window.

The probe is placed in parasternal position at site

of the greatest fluid collection in pericardial cavity

and the most direct access.

The diagnosis of hemopericardium sometimes can be difficult, therefore in any case of doubt the

more qualified specialist should be called to the aid. In poor or inconclusive images,

transesophageal echocardiography should always be performed in patients with stable

hemodynamic and clinical suspicion on cardiac injury.

Cardiac Contusion Blunt cardiac injury has been defined as the presence of wall motion abnormalities detected by

echocardiography, including either, or both, ventricles, following nonpenetrating chest trauma.

The left anterior descending coronary artery, tricuspid valve, and right ventricle are the most

commonly injured structures due to their proximity to the chest wall.

Patients with significant chest trauma (multiple rib fractures, pulmonary contusions, hemothorax,

major intrathoracic vascular injury) have an estimated 13% incidence of significant blunt cardiac

injury. Patients with blunt cardiac injury may present with a wide spectrum of signs and

symptoms ranging from asymptomatic to severe cardiac compromise. Arrhythmias and

conduction defects are the most common complications of blunt cardiac injury. There are many

reasons why a patient with blunt chest trauma may be hypotensive, hypoxic, tachycardic, or in

heart failure.

Current trauma guidelines recommend an admission ECG for all patients with suspected blunt

cardiac injury. Hemodynamically stable patients with a normal ECG require no further workup

for blunt cardiac injury, as the risk of serious complications is minimal. If the admission ECG is

abnormal, the patient should be admitted for continuous ECG monitoring for 24 to 48 hours.

Echocardiography should be used for patients with hemodynamic instability of unclear etiology,

an abnormal ECG, or cardiac arrhythmias with documented risk of blunt cardiac injury.

Repeat echocardiography in patients with blunt cardiac injury will often show normalization of

wall motion abnormalities.

Earlier echocardiographyc investigation was performed only by specialists in echocardiography,

but now intensive training of emergency physicians and trauma surgeons allows to perform

Emergency Echocardiоgraphy as limited echocardiography investigation focusing on the

detection urgent pathology of the heart and understanding of the causes of haemodynamic

instability of the patient (not only at a trauma, but also at other critical conditions).

Blunt abdominal trauma at pregnancy

About 7% of pregnant patients sustain an accidental injury sometime during pregnancy. The

greatest frequency of injuries is in the third trimester.

Motor vehicle accidents are the most common cause of injuries (approximately two-thirds of

cases) and 24% of pregnant patients with major injuries do not survive. The most common

intraabdominal injuries is placental abruption and splenic injuries, followed by liver and bowel

injuries. Uterine rupture occurs in 0.6% of cases and is almost always secondary to major trauma,

the rate of fetal death in this situation approaches 100%.

The fetus is well protected against injury from blunt trauma because it is encased in a fluid-filled

structure. The major cause of fetal death is maternal death. The fetal death rate approaches 80%

in cases of maternal shock. In cases of trauma in pregnancy, the primary consideration is saving

the mother's life, without which fetal death is inevitable.

The mother should be kept in the left lateral decubitus position during the third trimester to

prevent vena caval obstruction. The pregnant patient must be adequately and rapidly evaluated

by US in supine position, performing FAST as rapid screening of the maternal abdomen for free

fluid. After initial attention to the mother, US should be used as rapidly as circumstances permit

to investigate fetal cardiac activity and placental integrity. US is an excellent imaging modality

for assessment of fetal viability and placental separation.

Fetal cardiac activity should be assessed for presence and rate as bradycardia (HR less than 120

beats per minute) is a marker of fetal distress caused by poor perfusion or hypoxia (due to

maternal shock, hypoxia, placental abruption or rupture of the uterus). Blood may be shunted

away from the fetus before the mother exhibits obvious signs of hypotension. If fetal bradycardia

develops (heart rate less than 110 beats per minute), an immediate cesarean section becomes

mandatory.

Such injuries as a minor slip or fall can lead to fetal death, usually due to incomplete or complete

separation of the placenta. Therefore, monitoring of the fetal HR and assessment of placental

integrity is essential in the emergency department regardless of the severity of the injury.

It is axiomatic that one must monitor the pregnant patient and her fetus in the emergency

department for at least a few hours even in cases of minor trauma. In cases of major trauma, the

patient and fetus should be hospitalized and monitored for at least 24 hours.

CT is frequently the study of choice in major trauma at pregnancy. In situations in which the

patient‟s life can be saved, the necessary diagnostic procedures should be performed without

hesitation, because radiation exposure has smaller threat in comparison with danger of the

missed maternal trauma. In critical cases, CT, especially spiral CT, is often used to rapidly

provide the broadest diagnostic potential in the shortest time, especially in cases of head trauma.

Angiography for active bleeding and embolization may be needed in life-threatening situations.

Limitations of FAST

US is useful for diagnostic imaging in patients with trauma, but it has some limitations:

One drawback of US in the setting of major trauma is the limited availability of space and access

to the patient in the emergency setting. Unless the patient is fully undressed, the sonographer has

difficulty reaching all the regions of interest. Moreover, because the need to perform o ther

diagnostic evaluations ( physical examination, blood sampling, or electrocardiography) may be

as urgent as the need for imaging, the sonographer often must compete with or maneuver around

colleagues from other departments for access to the patient.

Patient movement during the examination is another issue: In some cases, the patient is

uncooperative or aggressive with the medical staff. The chest and abdominal wall movements

during resuscitation make it difficult to obtain accurate images.

Contamination of the patient with blood, dirt, or other substances is likely to complicate the

imaging evaluation. In patients with penetrating trauma, dressing material and foreign bodies

may obstruct access to the patient or may obscure part of the anatomy at US.

Patient obesity may make it difficult to obtain satisfactory results at US. In the obese patient, use

of a 2-MHZ transducer may be adequate for the exclusion of intraperitoneal fluid.

The presence of subcutaneous emphysema can precludes adequate US examination. Subcutaneous air from a pneumothorax that dissects inferiorly may collect over the liver or

spleen and prevent adequate imaging of the affected portion of the abdomen. This may be

particularly evident in the left upper quadrant, where the spleen provides only a small acoustic

window that can easily be obscured by air.

Subcutaneous emphysema in a 40-year-old man

with a left pneumothorax.

On a suboptimal longitudinal US image of the

left upper quadrant, the spleen is not visualized.

Open arrow indicates the diaphragm, solid

arrows indicate the region of the spleen.

If any area is not completely imaged at FAST,

the US examination should be considered

incomplete and CT or diagnostic peritoneal

lavage should be performed.

Old US machines or handheld devices can provide limited resolution. Also, in the trauma suite there is usually bright ambient light, which is necessary for physical examination or resuscitation

but which limits the visibility of the US monitor.

US is strongly operator dependent. The more experienced operators, the higher sensi tivity of

FAST. The definition developed by the FAST consensus conference specifies that 200 or more

supervised examinations must be performed to attain a sufficient skill level to perform FAST

reliably.

FAST examination is valuable tool for detecting hemoperitoneum but is inadequate for the

exclusion of organ injuries. Inclusion of assessment of the organ parenchyma, awareness of the

limitations and potential pitfalls of US, and close interaction with the surgical team will reduce

the risk of missed injury.

Clinical value of FAST results

Abdominal part of the FAST is focused only on looking for free fluid in abdominal cavity

without assessment of parenchymal organs, because sensitivity of method for detecting visceral

injuries is low.

The clinical value of a positive FAST is clear. A positive test helps rapid identification of

patients who require immediate exploratory laparotomy if they are hemodynamically unstable

and who require definitive assessment of the abdomen with CT if they are hemodynamically

stable.

The clinical value of a negative US scan is not clear and the treatment of patients with negative

findings at screening US is controversial. Injuries may be missed in patients with negative US

scans, including clinically important injuries that require intervention, if the diagnosis is based

on the presence of intraperitoneal fluid alone. Because negative sonographic findings do not

entirely exclude free fluid and may miss organs injuries if hemoperitoneum is not present.

In some centers, negative findings at US are routinely confirmed with repeat US or CT or

another test. In other centers, negative findings at US are confirmed in select cases on the basis

of clinical suspicion for missed injury.

In order to enhance the sensitivity of sonography for the detection of intraperitoneal injuries,

some investigators, mainly from Europe and Asia, have advocated to perform, rather than FAST,

a complete abdominal sonography study by a well-trained operator to depict both free fluid and

parenchymal injuries. Injuries of solid organs, particularly the liver and spleen, consist of

hyperechoic, hypoechoic, or mixed (both hyper- and hypoechoic) lesions. The presence of free

intraperitoneal gas suggests the presence of perforation of a hollow organ. Assessment of the

IVC and heart can be helpful, because IVC collapse with hyperdynamic heart indicates

hypovolemia as marker of blood loss, it is especially helpful in cases if hemoperitoneum is not

present.

Also Contrast enhanced ultrasound (CEUS) is able to safely demonstrate organ rupture, even

before hemoperitoneum.

US findings must be interpreted in the context of clinical findings. Certain clinical findings

mandate additional testing despite negative screening US findings, including persistent pain,

decreasing hematocrit levels, abdominal wall ecchymosis, hemodynamic instability. Hematuria

and fractures of the lower ribs, lumbar spine, and pelvis may also warrant additional tests.

Studies demonstrates that hematuria and fracture of the lower ribs, lumbar spine, or pelvis are

objective predictors of missed abdominal injury in patients with blunt abdominal trauma and

negative findings at initial screening with US, and such patients may benefit from additional

screening with computed tomography. These objective predictors should be assessed

immediately after the patient‟s arrival in the resuscitation suite.

The patients with these predictors for missed injury (high-risk patients) should be screened

immediately with CT rather than US. Patients who have no predictors for missed abdominal

injury (low-risk patients) should be screened with US and need not undergo CT or diagnostic

peritoneal lavage, both of which involve a risk of associated complications. Patients with

negative US scans should be admitted and observed at least 12–24 hours, because various

predictors of missed abdominal injuries may evolve over time.

Studies demonstrates that combination of negative US findings and negative clinical observation

virtually excludes abdominal injury in patients who are admitted and observed for at least 12–24

hours, and confirmation with other tests is unnecessary.

But some investigators, mainly from US, have advocated to perform CT as definitive diagnostic

test after negative FAST result, or even CT as a primary diagnostic study in stable patients.

Because negative US scan by itself is not adequate to exclude occult injury or even significant

injuries, also US is operator dependent. Operator experience plays an important role with regard

to the diagnostic yield, however, even in experienced hands, sonography appears not sufficiently

reliable to rule out organ injuries. CT remains the gold standard for abdominal trauma

assessment.

Not only is ultrasound not accurate for evaluating retroperitoneal hemorrhage or bowel injuries,

but it also cannot be relied upon to grade the severity of organ injury, detect active bleeding, or

isolate injury to a single organ.

Detecting hemoperitoneum or predicting the need for laparotomy are significant diagnostic

endpoints for the emergency physician, but it is also important to determine the extent of specific

organ injury. Recently this has become even more relevant as many surgeons are managing

splenic and liver injury nonoperatively. In most centers indications for laparotomy are currently

based on CT grading of organ injury.

These limitations of ultrasound are in competition with the fact that access, speed, and accuracy

of CT scanning has increased significantly in recent years. Therefore, in trauma centers, where

timely access to high-speed CT scanners is not limited, there is little sound evidence for

ultrasound supplanting CT scan in the diagnostic evaluation of the stable blunt abdominal trauma

patient. Trauma management incorporating FACTT (focused assessment with computed

tomography in trauma) enhances a rapid response to life-threatening problems and enables a

comprehensive assessment of the severity of each relevant injury.

Currently total-body CT (foot to head scan) is the preferential method in trauma centers,

associated to its indiscriminate and liberal use. CT-related complications are increased risk of

cancer and neprotoxicity and in case of extreme age patients, these frets should be kept in mind.

Unfortunately, unlimited access to abdominal CT scanning is not always available. Trauma

centers may be presented with multiple stable patients requiring CT scanning and ultrasound

may be used to triage which, and in what order, patients should be scanned. As well, patients can

present with blunt abdominal trauma to hospitals where there is limited or no access to a CT

scanner.

So, which type of study should be performed: US (including repeated US, clinical observation

with selection of patients for CT or other diagnostic tests) or CT as primary study in patients

with stable hemodynamic depends on clinical scenarios and institutions predilection.

Additional examinations at FAST

In the acute trauma situation, ultrasound can, in experienced hands, demonstrate more wide

applications, expanding ultrasound examination on dependency of clinical scenarios, if time

permits. All the components of the Extended FAST requires a significant amount of experience

and practice.

Look for pneumoperitoneum

Recently some specialists in FAST protocol includes detection of pneumoperitoneum, as indirect

confirmation of hollow viscus rupture. Since sonography has the same sensitivity and specificity

in revealing of free gas in abdominal cavity, as well as radiography. Sonography is able to reveal pneumoperitoneum in volume 5 ml and some investigations shows

the better sensitivity of sonography than radiography in detection of intraperitoneal free air.

СТ is the gold standard in detection of pneumoperitonium, its localization and volume, but since

for the majority of patients sonography is an initial method of investigation, so this method is

very valuable for rapid diagnosis of intraabdominal injuries (hollow viscus rupture) in patients

with unstable hemodynamic.

Normally, parietal peritoneum on the sonographic image looks as thin echogenic line located

below a muscular layer and a preperitoneal fat of the abdominal wall.

Below this echogenic line visualized intraabdominal organs sliding «to-and-fro» synchronously

with respiratory movements, also are visible peristaltic bowel loops.

Therefore peritoneal line which is looking as thin echogenic strip, is well visualized on interface

between anterior abdominal wall and moving structures of the abdominal cavity. At pneumoperitoneum the bubbles of gas are produced a sonographic appearance of focal

enhancement and thickening of the peritoneal stripe (at the level of parietal peritoneum).

The EPSS (Enhanced Peritoneal Stripe Sign) is a reliable and accurate sonographic sign for the

diagnosis of pneumoperitoneum with sensitivity and specificity about 100%.

Pneumoperitoneum on ultrasound is typically identified as a prominent hyperechoic peritoneal

stripe with reverberation artifacts. In the right upper quadrant, pneumoperitoneum is seen as

echogenic lines or spots with posterior ring-down or comet-tail artifacts between the anterior

abdominal wall and the liver, but sometimes can be without artifacts (if presence tiny bubbles of

gas).

A specific sign of pneumoperitoneum is enhancement of

the peritoneal stripe (peritoneal line looks much more

echogenic and thicker than normal peritoneal line).

Sonogram of the right upper quadrant shows area of

enhancement of the peritoneal stripe (large arrow)

representing intraperitoneal air with multiple horizontal

reverberation artifacts (ring-down artifacts).

Ring-down artifact produces multiple parallel lines of

similar length (open arrows).

Note normal adjacent peritoneal stripe (small arrows).

Pneumoperitoneum with posterior reverberation

artifact.

Prominent hyperechogenic peritoneal stripe

with corresponding horizontal reverberation artifacts

between the surface of the liver and the abdominal

wall.

Free intraperitoneal air.

Enhancement of peritoneal stripe without posterior

artifact (large arrow) representing tiny bubbles of

intraperitoneal air.

Note normal adjacent peritoneal stripe (small arrows).

At pneumoperitonium gas can be visualized in any part of abdomen, but the most frequent and

better intraperitoneal gas is visualized in epigastric area and in the right upper quadrant.

When assessing the abdomen for evidence of pneumoperitoneum, attention must be paid to

technique. The patient should be scanned in the supine with attention concentrated on the

epigastrium and right upper quadrant. The initial probe position is in the right paramedian

epigastric area (or midline) in the longitudinal direction (for air searching between the left liver

lobe and anterior abdominal wall). Then probe should be gradually displaced in right upper

quadrant, the anterior and right lateral aspects of the liver are scanned in each position (for air

searching between the right lobe of the liver and anterior abdominal wall).

Pneumoperitoneum will be visualized as echogenic lines or spots with posterior ring-down or

comet-tail artifacts between the anterior abdominal wall and the liver. Ring-down artifact

produces multiple parallel horizontal lines of similar length, whereas these lines gradually

decrease in length in comet-tail artifact.

Longitudinal scan in the right upper

quadrant.

Between anterior abdominal wall and

liver surface visualized a focal

enhancement of peritoneal stripe (large

arrow) representing tiny bubbles of

intraperitoneal air with a linear

reverberation artifact (comet-tail artifact).

Comet-tail artifact (dirty shadowing

artifact) – open arrows.

Note normal adjacent peritoneal stripe

(small arrows).

Pneumoperitoneum – peritoneal stripe enhancement

(large arrow) associated with multiple horizontal

reverberation artifacts (open arrows) and focal

enhancement of the peritoneal stripe (arrowhead)

without associated posterior artifact representing

small bubble gas.

Normal peritoneal stripe (small solid arrows).

An important sign of the pneumoperitoneum is “shifting phenomenon” whereby free air shifts

from the anterior to the lateral aspect of the liver as the patient turned from the supine to the left

lateral decubitus position.

Pneumoperitoneum (fig 1)

Sagittal upper midline US image obtained with the

patient supine shows a small area of enhancement of

the peritoneal stripe (arrow) with ring-down artifact

(arrowheads).

Pneumoperitoneum (fig 2)

Sagittal US image of the right upper quadrant,

obtained with the patient in the left decubitus

oblique position, shows that the area of enhancement

of the peritoneal stripe (arrow) has moved anterior to

the liver – “shifting phenomenon”.

In some patients, it may be difficult to differentiate pulmonary air from free intraabdominal air in the right upper quadrant, as the appearance produced may be that of a continuous line of

reverberation. Lee et al described a technique whereby the patient is evaluated during inspiration

and expiration. The pulmonary and pneumoperitoneal reverberation artifacts overlap during

inspiration but appear separate at expiration.

Effect of inspiration and expiration on detection of

pneumoperitoneum.

Sonogram A made on inspiration shows pneumoperitoneum

(P, open arrow) overlapped by lung (L, arrowheads).

Sonogram B made on expiration shows lung (L, arrowheads)

separated from pneumoperitoneum (P, open arrow).

Also US sign of pneumoperitoneum in patients with free abdominal fluid is the presence of air

bubbles within the fluid. They appear as floating echogenic foci with reverberation artifacts.

Free fluid with pneumoperitoneum.

Pneumoperitoneum – the hyperehogenic focus

representing a bubble gas (curved arrow) with a linear

reverberation artefact (comet-tail artifact) distal to gas

bubble detected in a free fluid (F).

comet-tail artifact (white arrow)

And may appear as floating echogenic foci in free fluid.

Free air may be detected anywhere in the abdomen as obvious enhancement of the peritoneal line

and thus can be distinguished from adjacent intraluminal gas.

Intraluminal gas is associated with a normal overlying peritoneal stripe, whereas the free

intraperitoneal air associated with an enhanced, thickened peritoneal stripe.

Intestinal gas echo.

Intraluminal bowel gas (curved arrows) always associated

with more superficial peritoneal stripe (small arrows).

Intraluminal bowel gas is located always under peritoneal

line.

Between peritoneal line and bowel gas visualized

hypoechoic or anechoic thin strip representing bowel wall.

Free intraperitoneal gas – enhancement of peritoneal

stripe (large straight arrow) associated with multiple

reverberation artifacts (open arrow).

Note adjacent intraluminal bowel gas (curved arrow)

with more superficial peritoneal stripe (small solid

arrows).

In doubtful cases the “shifting phenomenon” can help to differ free air from intraluminal air (as

the patient turned from the supine to the left lateral decubitus position thus will be visualized

rapid displacement of free air unlike intraluminal air).

A massive pneumoperitoneum can cause unexpected difficulty in obtaining of any images of

abdominal organs and should not be mistaken for significant amount of intraluminal gas (this is

similar to a situation at marked pneumothorax when unexpected difficulty at attempt to obtain

heart images from transthoracal access). But absence of more superficial echogenic peritoneal

stripe will help to diagnose pneumoperitoneum.

Recently was reported about a new sonographic technique (the scissors maneuver) for detection

of intraperitoneal free air superficial to the liver. The maneuver consists of applying and then

releasing slight pressure onto the abdominal wall with the caudal part of a parasagittaly oriented

linear-array probe. The sensitivity and specificity values of sonography and radiography were

identical in this study; sensitivity was 94% and specificity was 100% for both imaging

modalities. Thus sonography is an effective tool in the diagnosis of pneumoperitoneum, with

sensitivity and specificity equal to those of radiography. The scissors maneuver may be a useful

adjunct for improving the diagnostic yield of sonography.

Focused Sonography in diaphragmatic injury

Blaivas et al describe using M-mode to diagnose diaphragmatic injury. Normally, the diaphragm

moves synchronously with respiratory movements and becomes fixed after injury.

The image demonstrates normal diaphragmatic

movement in M-mode during the respiratory cycle.

The image illustrates the loss of diaphragmatic

movement.

Fixed M-mode image correlate with diaphragmatic

injury.

Focused Ocular Ultrasound

The resuscitation of serious closed head injuries demands the early identification of intracranial hemorrhage causing elevated intra-cranial pressure (ICP) amenable to surgical intervention.

While ICP monitoring is recommended in patients with decreased Glasgow Coma Scale (<8) and

an abnormal CT scan, hemodynamic instability from associated injuries requiring operative

intervention can result in significant delays in both imaging and monitor insertion. As such,

attempts have been made to develop a rapid, noninvasive method of ICP assessment.

Bedside ocular ultrasound for measuring optic nerve sheath diameter (ONSD) has been recently

proposed as a portable noninvasive method to rapid detection of increased intra-cranial pressure

(ICP) in patients with head trauma.

Ultrasonography of the optic nerve sheath gives the clinician an objective measurement to assess

for elevated intracranial pressure and this technique parallels the concept of papilledema as a

marker for increased ICP. However, optic nerve ultrasonography is arguably easier to perform

and more quantifiable than the presence or absence of papilledema.

This procedure is strongly supported by anatomy and physiology, and can be used as a screening

method for patients with suspected elevated ICP.

The optic nerve sheath is a direct

extension of the dura. The perineural

sheath travels from the brain to each orbit

and communicates pressure from the

CSF.

Therefore, increased ICP is transmitted to

the optic nerve, causing edema and

swelling of the nerve sheath. Any

intracranial process that elevates intracra-

nial pressure (ICP) will cause the optic

nerve sheath to dilate. This expansion of

the nerve sheath can be measured by

ultrasound.

A thick layer of gel is applied over the closed upper

eyelid. A high frequency linear probe is placed gently

on the patient‟s closed eyelid. Depth should be

adjusted so that the image of the eye fills the screen.

The optic nerve is visible posteriorly as a hypoechoic

linear region radiating away from globe.

For the nerve sheath shadow to be seen, the ultrasound

beam or plane needs to transect the nerve, which

enters the orbit at a slight angle. With gentle rocking

of the probe or moving slightly to the lateral edge of

the globe, the nerve sheath will usually come into

view.

The optic nerve sheath is measured 3 mm behind the globe, and the ONSD measurement is taken

within the visualized sheath.

Measurements should be performed in two planes, transverse and longitudinal by rotating the

probe ninety degrees, to ensure true diameters are measured.

For ocular nerve sheath measurements, the dark shadow of the optic

nerve should be identified posterior to the retina.

Normal optic nerve sheath diameter (D = 0.50 cm).

B - optic nerve sheath diameter (ONSD), measured 3 mm behind the

globe (A-A).

Values considered normal for ONSD are less than 5 mm in adults, less than 4.5 mm in children

aged 1 to 15 years, and less than 4 mm in infants. Diameters that are greater than these cutoff

values indicate an elevated ICP. Measurement of >5.0 mm has been shown to correlate with

elevated ICP (>20 mmHg) or evidence of increased ICP on CT scan of the head.

Dilated optic nerve sheath diameter (D = 0.61 cm) correlates

with elevated ICP.

Dilated optic nerve sheath diameter (D = 0.72 cm)

correlates with elevated ICP.

Optic nerve sheath diameter represents a potentially quick, noninvasive and sensitive bedside screening test for detecting raised ICP and the presence of intracranial hematoma needing

surgical intervention in head injury, utilizing readily available equipment and requiring a

minimal amount of training. It has all the advantages of ultrasound including being easily

repeatable for dynamic changes over time.

Focused Sonography in bony injury Ultrasound evaluation of extremity, rib, and sternal injury are valuable techniques that

potentially present advantages especially in the austere and military areas, were radiography

may not be readily available. Diagnosis of bony injuries may be more rapid by using ultrasound

over other modalities, even plain x-rays take a significant amount of time to be performed.

Ultrasound is used at the bedside concurrently with the overall trauma resuscitation, and may

potentially limit the patient‟s and treating team‟s exposure to ionizing radiation.

Multiple long-bone fractures may be a source of shock and can be quickly confirmed at the

bedside with EFAST and early detection of long-bone fractures can also aid in the early

stabilization of severely injured patients.

Studies demonstrates high accuracy (overall accuracy of 94%) among both physician and para-

medical clinicians in detecting long-bone fractures with minimal training.

Pitfalls in this technique include reduced accuracy with the small bones of the hands and feet, as

well as great reliance on user experience.

Location Sensitivity% Specificity%

Forearm/arm 92 100

Femur 83 100

Tibia/fibula 83 100

Hand/foot 50 100

Technique

A high-frequency linear probe should be used for assessment the superficial soft tissue and

bony structures. Subcutaneous tissue and muscle are readily visualized with ultrasound because

they transmit sound well. Bone acts as a bright reflector, giving a strong echogenic signal with

distal shadowing. The depth should be set to maximize imaging of the cortical interface.

Intense wave reflection is clearly illustrated the cortical bony anatomy (readily visible as an

unbroken, highly echogenic line), and making cortical disruption obvious.

Longitudinal scan of the long bone. Normal cortical

contour of bone (bright white line) – smooth and

uninterrupted.

The diagnosis of long bone fractures can be made by

assessing for a break in the normal cortical contour

of bones.

Transverse scan of the long bone. Normal cortex (arrow) –

smooth and uninterrupted.

Bony fractures are evident as a break in this echogenic line, representative of a break in the

cortex, or a step is detected in the bony outline when the fragment is displaced. The fracture is

often associated with a localized hematoma or soft-tissue swelling.

A fibula fracture with significant soft tissue swelling. Note

the cortical disruption (broken bright white line) with “step”

appearance.

The bone is first identified in cross-section and is initially scanned longitudinally with the probe

moved slowly across the point of maximal tenderness. The cortex is assessed for irregularities,

disruptions, or steps. Suspicious areas and regions of soft tissue swelling or hematoma are then

further assessed in a transverse plane. Although the longitudinal view is often more useful,

transverse views may also demonstrate these findings and give information as to the degree of

angulation or displacement. Perform ultrasound on the contralateral side to compare the anatomy

side by side if anatomy appears strange.

Probe position for femoral head.

Imaging of the femur should begin at the

distal femur by placing the probe superior

to the patella over the thigh laterally. The

femur should first be visualized in a

transverse plane to ensure proper

identification, and then the probe should be

rotated 90 degrees and the length of the

femur scanned by moving the probe

proximally. The probe should be angled at

the femoral neck, with the indicator toward

the pubic symphysis, to visualize the

femoral neck, head, and pelvic acetabulum.

Displaced fracture of the femoral diaphysis. The proximal

and distal segments are 20 mm distant, without overriding

(arrows).

Comminuted fibula fracture with cortical

interruption.

Comminuted fibula fracture on X-ray

image....……………….

Clavicle fracture, with cortical interruption with

displacement.

Clavicle fractures are easily identified by both

radiography and ultrasound. In some cases, however,

ultrasound may be more advantageous. Because many

of these fractures occur in children, a quick bedside

diagnosis without any exposure to ionizing

radiation is desirable.

Also US may be used in the diagnosis of rib fracture. Studies have found that sonosraphy is much more sensitive than plain radiography in detecting rib and sternal fractures (up to 50–88%

of rib fractures are undetected on conventional chest X-rays). Likewise, US has been shown to be

more sensitive in the detection of chondral rib fractures and cartilage separations compared with

chest X-rays. US can visualize the costal cartilage as well as the osseous part of the rib.

Rib fractures occur with a rate of 35–40% in thoracic trauma. The fourth through 10th ribs are

the most often fractured. The rate of associated injury in patients with rib fractures is high.

Potentially severe complications include:

Pneumothorax

Hemothorax

Pulmonary contusion

Flail chest

Vascular and nerve damage (especially with trauma to the upper chest)

Abdominal organ injury (particularly with trauma to the lower thorax).

The localization of the fractured rib has a clinical significance to further evaluate a possible

associated visceral injury. Fractures of the first three ribs can indicate significant trauma to the

trachea, bronchi and main vascular structures and fractures of the lower ribs should arouse

suspicion for a possible injury to spleen, liver, kidneys or diaphragm.

Sonography is best performed along the line of the rib and over the site of maximum tenderness.

Rib fracture with a step of 1.5 mm. This fracture could not

be seen on X-rays. No accompanying hematoma above the

fracture site

Traumatic rib fracture. Sonogram shows cortical disruption

(arrow) and hematoma formation (arrowheads).

When a normal rib is scanned along its long axis, the anterior

cortex appears as a smooth, continuous echogenic line. In this

example of an acute rib fracture, a visible gap with loss of

continuity of the anterior cortex of the rib is seen. A small,

hypoechoic hematoma bridges the gap.

The imaging of a rib fracture with US is not a complicated procedure, and can be performed by

the clinicians as well. However, examination has a number of disadvantages: time-consuming,

depending on the operator‟s skills and may be inaccessible for the subscapular ribs and the

infraclavicular portion of the first rib, which are uncommon sites for rib fractures. In addition,

large breasts and obesity may also limit the optimal detection of rib fractures.

The choice of which test to use in a patient with a suspected rib fracture greatly depends on the

clinical scenarios. In stable patients with penetrating or major chest or abdominal trauma, CT is

the study of choice. It provides the most information about associated injuries, and accurately

detects rib fractures. This helps target treatment of associated injuries, and helps identify patients

at higher risk, such as those with significant vascular, pulmonary, or abdominal injuries and

those with a greater number of fractures.

Sternal fractures occur in up to 10% of casualties who sustain significant blunt trauma to

the chest. The most frequent mechanism of injury associated with sternal fracture is a motor

vehicle crash where the driver is thrown forward against the steering wheel. Sternal fractures are

usually diagnosed on a lateral radiograph, however occasionally these injuries may not be visible

on the X-ray film. Studies shows that ultrasound to be more accurate than radiographs with

sensitivity of 90–100%.

Ultrasound assessment of the sternum should be undertaken where there is clinical suspicion of

sternal injury from the mechanism of injury and appropriate tenderness on examination.

Ultrasound of sternal fracture demonstrating interruption of

the cortex (arrow).

Also ultrasound can detect skull fractures. Ultrasound has 94% specificity and 82% sensitivity

for detecting closed-head skull fractures. Bedside ultrasound can help identify skull fractures in

children and might be a useful tool in deciding which patients need further imaging.

Ultrasound of the skull fracture (arrow)...........................

Transverse sonogram shows minimally displaced fracture of rib (long arrow). Note hematoma

Bedside sonography also greatly improves the success rates of emergency procedures in trauma

patients. These include vascular access (placement of central venous catheters),

pericardiocentesis, thoracocentesis, control of correct placement of the intubation tube.

With the advent of portable, modern equipments and the growth in experience of focussed

assessment with sonography for trauma (FAST) among emergency physicians and surgeons, the

complete range of applications for ultrasound diagnosis has yet to be determined.